sorted imports statements and apply "black" formatting (#583)

diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 79f025d..1f6698f 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml

@@ -6,8 +6,17 @@
     rev: 4.0.1.1
     hooks:
       - id: buildifier
-        args: &args
+        args: &args 
           # Keep this argument in sync with .bazelci/presubmit.yaml
           - --warnings=all
       - id: buildifier-lint
         args: *args
+  - repo: https://github.com/pycqa/isort
+    rev: 5.10.1
+    hooks:
+      - id: isort
+        name: isort (python)
+  - repo: https://github.com/psf/black
+    rev: 21.12b0
+    hooks:
+      - id: black

diff --git a/examples/build_file_generation/__init__.py b/examples/build_file_generation/__init__.py
index ce47b77..11b15b1 100644
--- a/examples/build_file_generation/__init__.py
+++ b/examples/build_file_generation/__init__.py

@@ -1 +1 @@
-print("hello")
\ No newline at end of file
+print("hello")

diff --git a/examples/pip_install/main.py b/examples/pip_install/main.py
index fdb3c65..b65ad0e 100644
--- a/examples/pip_install/main.py
+++ b/examples/pip_install/main.py

@@ -1,7 +1,9 @@
 import boto3
 
+
 def the_dir():
     return dir(boto3)
 
+
 if __name__ == "__main__":
     print(the_dir())

diff --git a/examples/pip_install/pip_install_test.py b/examples/pip_install/pip_install_test.py
index 1e53c12..e865dea 100644
--- a/examples/pip_install/pip_install_test.py
+++ b/examples/pip_install/pip_install_test.py

@@ -1,9 +1,9 @@
 #!/usr/bin/env python3
 
-from pathlib import Path
 import os
 import subprocess
 import unittest
+from pathlib import Path
 
 
 class PipInstallTest(unittest.TestCase):
@@ -16,13 +16,23 @@
         entry_point = Path(env)
         self.assertTrue(entry_point.exists())
 
-        proc = subprocess.run([entry_point, "--version"], check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        proc = subprocess.run(
+            [entry_point, "--version"],
+            check=True,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+        )
         self.assertEqual(proc.stdout.decode("utf-8").strip(), "yamllint 1.26.3")
 
         # yamllint entry_point is of the form `def run(argv=None):`
         with self.assertRaises(subprocess.CalledProcessError) as context:
-            subprocess.run([entry_point, "--option-does-not-exist"], check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-        self.assertIn('returned non-zero exit status 2', str(context.exception))
+            subprocess.run(
+                [entry_point, "--option-does-not-exist"],
+                check=True,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE,
+            )
+        self.assertIn("returned non-zero exit status 2", str(context.exception))
 
     def test_entry_point_int_return(self):
         env = os.environ.get("SPHINX_BUILD_ENTRY_POINT")
@@ -31,14 +41,24 @@
         entry_point = Path(env)
         self.assertTrue(entry_point.exists())
 
-        proc = subprocess.run([entry_point, "--version"], check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        proc = subprocess.run(
+            [entry_point, "--version"],
+            check=True,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+        )
         # sphinx-build uses args[0] for its name, only assert the version here
-        self.assertTrue(proc.stdout.decode("utf-8").strip().endswith('4.2.0'))
+        self.assertTrue(proc.stdout.decode("utf-8").strip().endswith("4.2.0"))
 
         # sphinx-build entry_point is of the form `def main(argv: List[str] = sys.argv[1:]) -> int:`
         with self.assertRaises(subprocess.CalledProcessError) as context:
-            subprocess.run([entry_point, "--option-does-not-exist"], check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-        self.assertIn('returned non-zero exit status 2', str(context.exception))
+            subprocess.run(
+                [entry_point, "--option-does-not-exist"],
+                check=True,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE,
+            )
+        self.assertIn("returned non-zero exit status 2", str(context.exception))
 
     def test_data(self):
         env = os.environ.get("WHEEL_DATA_CONTENTS")

diff --git a/examples/pip_install/test.py b/examples/pip_install/test.py
index 0b3b333..0859a28 100644
--- a/examples/pip_install/test.py
+++ b/examples/pip_install/test.py

@@ -1,9 +1,12 @@
 import unittest
+
 import main
 
+
 class ExampleTest(unittest.TestCase):
     def test_main(self):
         self.assertIn("set_stream_logger", main.the_dir())
 
-if __name__ == '__main__':
-  unittest.main()
+
+if __name__ == "__main__":
+    unittest.main()

diff --git a/examples/pip_parse/pip_parse_test.py b/examples/pip_parse/pip_parse_test.py
index 361d59f..8d8846a 100644
--- a/examples/pip_parse/pip_parse_test.py
+++ b/examples/pip_parse/pip_parse_test.py

@@ -1,9 +1,9 @@
 #!/usr/bin/env python3
 
-from pathlib import Path
 import os
 import subprocess
 import unittest
+from pathlib import Path
 
 
 class PipInstallTest(unittest.TestCase):
@@ -16,13 +16,23 @@
         entry_point = Path(env)
         self.assertTrue(entry_point.exists())
 
-        proc = subprocess.run([entry_point, "--version"], check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        proc = subprocess.run(
+            [entry_point, "--version"],
+            check=True,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+        )
         self.assertEqual(proc.stdout.decode("utf-8").strip(), "yamllint 1.26.3")
 
         # yamllint entry_point is of the form `def run(argv=None):`
         with self.assertRaises(subprocess.CalledProcessError) as context:
-            subprocess.run([entry_point, "--option-does-not-exist"], check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-        self.assertIn('returned non-zero exit status 2', str(context.exception))
+            subprocess.run(
+                [entry_point, "--option-does-not-exist"],
+                check=True,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE,
+            )
+        self.assertIn("returned non-zero exit status 2", str(context.exception))
 
     def test_entry_point_int_return(self):
         env = os.environ.get("SPHINX_BUILD_ENTRY_POINT")
@@ -31,14 +41,24 @@
         entry_point = Path(env)
         self.assertTrue(entry_point.exists())
 
-        proc = subprocess.run([entry_point, "--version"], check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        proc = subprocess.run(
+            [entry_point, "--version"],
+            check=True,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+        )
         # sphinx-build uses args[0] for its name, only assert the version here
-        self.assertTrue(proc.stdout.decode("utf-8").strip().endswith('4.2.0'))
+        self.assertTrue(proc.stdout.decode("utf-8").strip().endswith("4.2.0"))
 
         # sphinx-build entry_point is of the form `def main(argv: List[str] = sys.argv[1:]) -> int:`
         with self.assertRaises(subprocess.CalledProcessError) as context:
-            subprocess.run([entry_point, "--option-does-not-exist"], check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-        self.assertIn('returned non-zero exit status 2', str(context.exception))
+            subprocess.run(
+                [entry_point, "--option-does-not-exist"],
+                check=True,
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE,
+            )
+        self.assertIn("returned non-zero exit status 2", str(context.exception))
 
     def test_data(self):
         env = os.environ.get("WHEEL_DATA_CONTENTS")

diff --git a/examples/pip_parse/test.py b/examples/pip_parse/test.py
index 3415a32..e1f97f1 100644
--- a/examples/pip_parse/test.py
+++ b/examples/pip_parse/test.py

@@ -1,4 +1,5 @@
 import unittest
+
 import main
 
 
@@ -7,5 +8,5 @@
         self.assertEqual("2.25.1", main.version())
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()

diff --git a/examples/py_import/py_import_test.py b/examples/py_import/py_import_test.py
index 1d7212d..1f5aa71 100644
--- a/examples/py_import/py_import_test.py
+++ b/examples/py_import/py_import_test.py

@@ -18,24 +18,23 @@
 
 
 class HelloWorldTest(unittest.TestCase):
+    def test_helloworld(self):
+        hw = helloworld.HelloWorld()
+        hw.SayHello()
 
-  def test_helloworld(self):
-    hw = helloworld.HelloWorld()
-    hw.SayHello()
+    def test_helloworld_async(self):
+        hw = helloworld.HelloWorld()
+        hw.SayHelloAsync()
+        hw.Stop()
 
-  def test_helloworld_async(self):
-    hw = helloworld.HelloWorld()
-    hw.SayHelloAsync()
-    hw.Stop()
-
-  def test_helloworld_multiple(self):
-    hw = helloworld.HelloWorld()
-    hw.SayHelloAsync()
-    hw.SayHelloAsync()
-    hw.SayHelloAsync()
-    hw.SayHelloAsync()
-    hw.Stop()
+    def test_helloworld_multiple(self):
+        hw = helloworld.HelloWorld()
+        hw.SayHelloAsync()
+        hw.SayHelloAsync()
+        hw.SayHelloAsync()
+        hw.SayHelloAsync()
+        hw.Stop()
 
 
-if __name__ == '__main__':
-  unittest.main()
+if __name__ == "__main__":
+    unittest.main()

diff --git a/examples/relative_requirements/relative_package/setup.py b/examples/relative_requirements/relative_package/setup.py
index 3fd85c1..052b519 100644
--- a/examples/relative_requirements/relative_package/setup.py
+++ b/examples/relative_requirements/relative_package/setup.py

@@ -1,7 +1,7 @@
 from setuptools import setup
 
 setup(
-    name='relative_package_name',
-    version='1.0.0',
-    packages=['relative_package_name'],
+    name="relative_package_name",
+    version="1.0.0",
+    packages=["relative_package_name"],
 )

diff --git a/examples/wheel/lib/module_with_data.py b/examples/wheel/lib/module_with_data.py
index 7b28643..6b661eb 100644
--- a/examples/wheel/lib/module_with_data.py
+++ b/examples/wheel/lib/module_with_data.py

@@ -12,5 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+
 def function():
     return "foo"

diff --git a/examples/wheel/lib/simple_module.py b/examples/wheel/lib/simple_module.py
index fb26a51..b69ae2b 100644
--- a/examples/wheel/lib/simple_module.py
+++ b/examples/wheel/lib/simple_module.py

@@ -12,5 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+
 def function():
     return "bar"

diff --git a/examples/wheel/main.py b/examples/wheel/main.py
index 3068ff0..7c4d323 100644
--- a/examples/wheel/main.py
+++ b/examples/wheel/main.py

@@ -26,5 +26,5 @@
     print(simple_module.function())
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main()

diff --git a/examples/wheel/wheel_test.py b/examples/wheel/wheel_test.py
index e1d7b18..c28accd 100644
--- a/examples/wheel/wheel_test.py
+++ b/examples/wheel/wheel_test.py

@@ -19,77 +19,101 @@
 
 class WheelTest(unittest.TestCase):
     def test_py_library_wheel(self):
-        filename = os.path.join(os.environ['TEST_SRCDIR'],
-                                'rules_python',
-                                'examples', 'wheel',
-                                'example_minimal_library-0.0.1-py3-none-any.whl')
+        filename = os.path.join(
+            os.environ["TEST_SRCDIR"],
+            "rules_python",
+            "examples",
+            "wheel",
+            "example_minimal_library-0.0.1-py3-none-any.whl",
+        )
         with zipfile.ZipFile(filename) as zf:
             self.assertEquals(
                 zf.namelist(),
-                ['examples/wheel/lib/module_with_data.py',
-                 'examples/wheel/lib/simple_module.py',
-                 'example_minimal_library-0.0.1.dist-info/WHEEL',
-                 'example_minimal_library-0.0.1.dist-info/METADATA',
-                 'example_minimal_library-0.0.1.dist-info/RECORD'])
+                [
+                    "examples/wheel/lib/module_with_data.py",
+                    "examples/wheel/lib/simple_module.py",
+                    "example_minimal_library-0.0.1.dist-info/WHEEL",
+                    "example_minimal_library-0.0.1.dist-info/METADATA",
+                    "example_minimal_library-0.0.1.dist-info/RECORD",
+                ],
+            )
 
     def test_py_package_wheel(self):
-        filename = os.path.join(os.environ['TEST_SRCDIR'],
-                                'rules_python',
-                                'examples', 'wheel',
-                                'example_minimal_package-0.0.1-py3-none-any.whl')
+        filename = os.path.join(
+            os.environ["TEST_SRCDIR"],
+            "rules_python",
+            "examples",
+            "wheel",
+            "example_minimal_package-0.0.1-py3-none-any.whl",
+        )
         with zipfile.ZipFile(filename) as zf:
             self.assertEquals(
                 zf.namelist(),
-                ['examples/wheel/lib/data.txt',
-                 'examples/wheel/lib/module_with_data.py',
-                 'examples/wheel/lib/simple_module.py',
-                 'examples/wheel/main.py',
-                 'example_minimal_package-0.0.1.dist-info/WHEEL',
-                 'example_minimal_package-0.0.1.dist-info/METADATA',
-                 'example_minimal_package-0.0.1.dist-info/RECORD'])
+                [
+                    "examples/wheel/lib/data.txt",
+                    "examples/wheel/lib/module_with_data.py",
+                    "examples/wheel/lib/simple_module.py",
+                    "examples/wheel/main.py",
+                    "example_minimal_package-0.0.1.dist-info/WHEEL",
+                    "example_minimal_package-0.0.1.dist-info/METADATA",
+                    "example_minimal_package-0.0.1.dist-info/RECORD",
+                ],
+            )
 
     def test_customized_wheel(self):
-        filename = os.path.join(os.environ['TEST_SRCDIR'],
-                                'rules_python',
-                                'examples', 'wheel',
-                                'example_customized-0.0.1-py3-none-any.whl')
+        filename = os.path.join(
+            os.environ["TEST_SRCDIR"],
+            "rules_python",
+            "examples",
+            "wheel",
+            "example_customized-0.0.1-py3-none-any.whl",
+        )
         with zipfile.ZipFile(filename) as zf:
             self.assertEquals(
                 zf.namelist(),
-                ['examples/wheel/lib/data.txt',
-                 'examples/wheel/lib/module_with_data.py',
-                 'examples/wheel/lib/simple_module.py',
-                 'examples/wheel/main.py',
-                 'example_customized-0.0.1.dist-info/WHEEL',
-                 'example_customized-0.0.1.dist-info/METADATA',
-                 'example_customized-0.0.1.dist-info/entry_points.txt',
-                 'example_customized-0.0.1.dist-info/RECORD'])
-            record_contents = zf.read(
-                'example_customized-0.0.1.dist-info/RECORD')
-            wheel_contents = zf.read(
-                'example_customized-0.0.1.dist-info/WHEEL')
-            metadata_contents = zf.read(
-                'example_customized-0.0.1.dist-info/METADATA')
+                [
+                    "examples/wheel/lib/data.txt",
+                    "examples/wheel/lib/module_with_data.py",
+                    "examples/wheel/lib/simple_module.py",
+                    "examples/wheel/main.py",
+                    "example_customized-0.0.1.dist-info/WHEEL",
+                    "example_customized-0.0.1.dist-info/METADATA",
+                    "example_customized-0.0.1.dist-info/entry_points.txt",
+                    "example_customized-0.0.1.dist-info/RECORD",
+                ],
+            )
+            record_contents = zf.read("example_customized-0.0.1.dist-info/RECORD")
+            wheel_contents = zf.read("example_customized-0.0.1.dist-info/WHEEL")
+            metadata_contents = zf.read("example_customized-0.0.1.dist-info/METADATA")
             entry_point_contents = zf.read(
-                'example_customized-0.0.1.dist-info/entry_points.txt')
+                "example_customized-0.0.1.dist-info/entry_points.txt"
+            )
             # The entries are guaranteed to be sorted.
-            self.assertEquals(record_contents, b"""\
+            self.assertEquals(
+                record_contents,
+                b"""\
 example_customized-0.0.1.dist-info/METADATA,sha256=TeeEmokHE2NWjkaMcVJuSAq4_AXUoIad2-SLuquRmbg,372
 example_customized-0.0.1.dist-info/RECORD,,
 example_customized-0.0.1.dist-info/WHEEL,sha256=sobxWSyDDkdg_rinUth-jxhXHqoNqlmNMJY3aTZn2Us,91
 example_customized-0.0.1.dist-info/entry_points.txt,sha256=pqzpbQ8MMorrJ3Jp0ntmpZcuvfByyqzMXXi2UujuXD0,137
 examples/wheel/lib/data.txt,sha256=9vJKEdfLu8bZRArKLroPZJh1XKkK3qFMXiM79MBL2Sg,12
-examples/wheel/lib/module_with_data.py,sha256=K_IGAq_CHcZX0HUyINpD1hqSKIEdCn58d9E9nhWF2EA,636
-examples/wheel/lib/simple_module.py,sha256=72-91Dm6NB_jw-7wYQt7shzdwvk5RB0LujIah8g7kr8,636
-examples/wheel/main.py,sha256=xnha0jPnVBJt3LUQRbLf7rFA5njczSdd3gm3kSyQJZw,909
-""")
-            self.assertEquals(wheel_contents, b"""\
+examples/wheel/lib/module_with_data.py,sha256=8s0Khhcqz3yVsBKv2IB5u4l4TMKh7-c_V6p65WVHPms,637
+examples/wheel/lib/simple_module.py,sha256=z2hwciab_XPNIBNH8B1Q5fYgnJvQTeYf0ZQJpY8yLLY,637
+examples/wheel/main.py,sha256=sgg5iWN_9inYBjm6_Zw27hYdmo-l24fA-2rfphT-IlY,909
+""",
+            )
+            self.assertEquals(
+                wheel_contents,
+                b"""\
 Wheel-Version: 1.0
 Generator: bazel-wheelmaker 1.0
 Root-Is-Purelib: true
 Tag: py3-none-any
-""")
-            self.assertEquals(metadata_contents, b"""\
+""",
+            )
+            self.assertEquals(
+                metadata_contents,
+                b"""\
 Metadata-Version: 2.1
 Name: example_customized
 Version: 0.0.1
@@ -102,112 +126,151 @@
 Requires-Dist: pytest
 
 This is a sample description of a wheel.
-""")
-            self.assertEquals(entry_point_contents, b"""\
+""",
+            )
+            self.assertEquals(
+                entry_point_contents,
+                b"""\
 [console_scripts]
 another = foo.bar:baz
 customized_wheel = examples.wheel.main:main
 
 [group2]
 first = first.main:f
-second = second.main:s""")
+second = second.main:s""",
+            )
 
     def test_filename_escaping(self):
-        filename = os.path.join(os.environ['TEST_SRCDIR'],
-                                'rules_python',
-                                'examples', 'wheel',
-                                'file_name_escaping-0.0.1_r7-py3-none-any.whl')
+        filename = os.path.join(
+            os.environ["TEST_SRCDIR"],
+            "rules_python",
+            "examples",
+            "wheel",
+            "file_name_escaping-0.0.1_r7-py3-none-any.whl",
+        )
         with zipfile.ZipFile(filename) as zf:
             self.assertEquals(
                 zf.namelist(),
-                ['examples/wheel/lib/data.txt',
-                 'examples/wheel/lib/module_with_data.py',
-                 'examples/wheel/lib/simple_module.py',
-                 'examples/wheel/main.py',
-                 # PEP calls for replacing only in the archive filename.
-                 # Alas setuptools also escapes in the dist-info directory
-                 # name, so let's be compatible.
-                 'file_name_escaping-0.0.1_r7.dist-info/WHEEL',
-                 'file_name_escaping-0.0.1_r7.dist-info/METADATA',
-                 'file_name_escaping-0.0.1_r7.dist-info/RECORD'])
+                [
+                    "examples/wheel/lib/data.txt",
+                    "examples/wheel/lib/module_with_data.py",
+                    "examples/wheel/lib/simple_module.py",
+                    "examples/wheel/main.py",
+                    # PEP calls for replacing only in the archive filename.
+                    # Alas setuptools also escapes in the dist-info directory
+                    # name, so let's be compatible.
+                    "file_name_escaping-0.0.1_r7.dist-info/WHEEL",
+                    "file_name_escaping-0.0.1_r7.dist-info/METADATA",
+                    "file_name_escaping-0.0.1_r7.dist-info/RECORD",
+                ],
+            )
             metadata_contents = zf.read(
-                'file_name_escaping-0.0.1_r7.dist-info/METADATA')
-            self.assertEquals(metadata_contents, b"""\
+                "file_name_escaping-0.0.1_r7.dist-info/METADATA"
+            )
+            self.assertEquals(
+                metadata_contents,
+                b"""\
 Metadata-Version: 2.1
 Name: file~~name-escaping
 Version: 0.0.1-r7
 
 UNKNOWN
-""")
+""",
+            )
 
     def test_custom_package_root_wheel(self):
-        filename = os.path.join(os.environ['TEST_SRCDIR'],
-                                'rules_python',
-                                'examples', 'wheel',
-                                'example_custom_package_root-0.0.1-py3-none-any.whl')
+        filename = os.path.join(
+            os.environ["TEST_SRCDIR"],
+            "rules_python",
+            "examples",
+            "wheel",
+            "example_custom_package_root-0.0.1-py3-none-any.whl",
+        )
 
         with zipfile.ZipFile(filename) as zf:
             self.assertEquals(
                 zf.namelist(),
-                ['wheel/lib/data.txt',
-                 'wheel/lib/module_with_data.py',
-                 'wheel/lib/simple_module.py',
-                 'wheel/main.py',
-                 'example_custom_package_root-0.0.1.dist-info/WHEEL',
-                 'example_custom_package_root-0.0.1.dist-info/METADATA',
-                 'example_custom_package_root-0.0.1.dist-info/RECORD'])
+                [
+                    "wheel/lib/data.txt",
+                    "wheel/lib/module_with_data.py",
+                    "wheel/lib/simple_module.py",
+                    "wheel/main.py",
+                    "example_custom_package_root-0.0.1.dist-info/WHEEL",
+                    "example_custom_package_root-0.0.1.dist-info/METADATA",
+                    "example_custom_package_root-0.0.1.dist-info/RECORD",
+                ],
+            )
 
     def test_custom_package_root_multi_prefix_wheel(self):
-        filename = os.path.join(os.environ['TEST_SRCDIR'],
-                                'rules_python',
-                                'examples', 'wheel',
-                                'example_custom_package_root_multi_prefix-0.0.1-py3-none-any.whl')
+        filename = os.path.join(
+            os.environ["TEST_SRCDIR"],
+            "rules_python",
+            "examples",
+            "wheel",
+            "example_custom_package_root_multi_prefix-0.0.1-py3-none-any.whl",
+        )
 
         with zipfile.ZipFile(filename) as zf:
             self.assertEquals(
                 zf.namelist(),
-                ['data.txt',
-                 'module_with_data.py',
-                 'simple_module.py',
-                 'main.py',
-                 'example_custom_package_root_multi_prefix-0.0.1.dist-info/WHEEL',
-                 'example_custom_package_root_multi_prefix-0.0.1.dist-info/METADATA',
-                 'example_custom_package_root_multi_prefix-0.0.1.dist-info/RECORD'])
+                [
+                    "data.txt",
+                    "module_with_data.py",
+                    "simple_module.py",
+                    "main.py",
+                    "example_custom_package_root_multi_prefix-0.0.1.dist-info/WHEEL",
+                    "example_custom_package_root_multi_prefix-0.0.1.dist-info/METADATA",
+                    "example_custom_package_root_multi_prefix-0.0.1.dist-info/RECORD",
+                ],
+            )
 
     def test_custom_package_root_multi_prefix_reverse_order_wheel(self):
-        filename = os.path.join(os.environ['TEST_SRCDIR'],
-                                'rules_python',
-                                'examples', 'wheel',
-                                'example_custom_package_root_multi_prefix_reverse_order-0.0.1-py3-none-any.whl')
+        filename = os.path.join(
+            os.environ["TEST_SRCDIR"],
+            "rules_python",
+            "examples",
+            "wheel",
+            "example_custom_package_root_multi_prefix_reverse_order-0.0.1-py3-none-any.whl",
+        )
 
         with zipfile.ZipFile(filename) as zf:
             self.assertEquals(
                 zf.namelist(),
-                ['lib/data.txt',
-                 'lib/module_with_data.py',
-                 'lib/simple_module.py',
-                 'main.py',
-                 'example_custom_package_root_multi_prefix_reverse_order-0.0.1.dist-info/WHEEL',
-                 'example_custom_package_root_multi_prefix_reverse_order-0.0.1.dist-info/METADATA',
-                 'example_custom_package_root_multi_prefix_reverse_order-0.0.1.dist-info/RECORD'])
+                [
+                    "lib/data.txt",
+                    "lib/module_with_data.py",
+                    "lib/simple_module.py",
+                    "main.py",
+                    "example_custom_package_root_multi_prefix_reverse_order-0.0.1.dist-info/WHEEL",
+                    "example_custom_package_root_multi_prefix_reverse_order-0.0.1.dist-info/METADATA",
+                    "example_custom_package_root_multi_prefix_reverse_order-0.0.1.dist-info/RECORD",
+                ],
+            )
 
     def test_python_requires_wheel(self):
-        filename = os.path.join(os.environ['TEST_SRCDIR'],
-                                'rules_python',
-                                'examples', 'wheel',
-                                'example_python_requires_in_a_package-0.0.1-py3-none-any.whl')
+        filename = os.path.join(
+            os.environ["TEST_SRCDIR"],
+            "rules_python",
+            "examples",
+            "wheel",
+            "example_python_requires_in_a_package-0.0.1-py3-none-any.whl",
+        )
         with zipfile.ZipFile(filename) as zf:
             metadata_contents = zf.read(
-                'example_python_requires_in_a_package-0.0.1.dist-info/METADATA')
+                "example_python_requires_in_a_package-0.0.1.dist-info/METADATA"
+            )
             # The entries are guaranteed to be sorted.
-            self.assertEquals(metadata_contents, b"""\
+            self.assertEquals(
+                metadata_contents,
+                b"""\
 Metadata-Version: 2.1
 Name: example_python_requires_in_a_package
 Version: 0.0.1
 Requires-Python: >=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*
 
 UNKNOWN
-""")
+""",
+            )
 
     def test_python_abi3_binary_wheel(self):
         filename = os.path.join(
@@ -247,20 +310,26 @@
             )
 
     def test_genrule_creates_directory_and_is_included_in_wheel(self):
-        filename = os.path.join(os.environ['TEST_SRCDIR'],
-                                'rules_python',
-                                'examples', 'wheel',
-                                'use_genrule_with_dir_in_outs-0.0.1-py3-none-any.whl')
+        filename = os.path.join(
+            os.environ["TEST_SRCDIR"],
+            "rules_python",
+            "examples",
+            "wheel",
+            "use_genrule_with_dir_in_outs-0.0.1-py3-none-any.whl",
+        )
 
         with zipfile.ZipFile(filename) as zf:
             self.assertEquals(
                 zf.namelist(),
-                ['examples/wheel/main.py',
-                 'examples/wheel/someDir/foo.py',
-                 'use_genrule_with_dir_in_outs-0.0.1.dist-info/WHEEL',
-                 'use_genrule_with_dir_in_outs-0.0.1.dist-info/METADATA',
-                 'use_genrule_with_dir_in_outs-0.0.1.dist-info/RECORD'])
+                [
+                    "examples/wheel/main.py",
+                    "examples/wheel/someDir/foo.py",
+                    "use_genrule_with_dir_in_outs-0.0.1.dist-info/WHEEL",
+                    "use_genrule_with_dir_in_outs-0.0.1.dist-info/METADATA",
+                    "use_genrule_with_dir_in_outs-0.0.1.dist-info/RECORD",
+                ],
+            )
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()

diff --git a/gazelle/modules_mapping/builder.py b/gazelle/modules_mapping/builder.py
index 352bfcb..3b471c0 100644
--- a/gazelle/modules_mapping/builder.py
+++ b/gazelle/modules_mapping/builder.py

@@ -67,4 +67,4 @@
         help="The number of concurrent build jobs to be executed.",
     )
     args = parser.parse_args()
-    exit(main(args.jobs, args.wheels))
\ No newline at end of file
+    exit(main(args.jobs, args.wheels))

diff --git a/gazelle/modules_mapping/generator.py b/gazelle/modules_mapping/generator.py
index 44cfcf6..6ee654c 100644
--- a/gazelle/modules_mapping/generator.py
+++ b/gazelle/modules_mapping/generator.py

@@ -19,10 +19,9 @@
     def dig_wheel(self, wheel):
         mapping = {}
         wheel_paths = glob.glob(wheel["path"])
-        assert (
-            len(wheel_paths) != 0
-        ), "wheel not found for {}: searched for {}".format(
-            wheel["name"], wheel["path"],
+        assert len(wheel_paths) != 0, "wheel not found for {}: searched for {}".format(
+            wheel["name"],
+            wheel["path"],
         )
         wheel_path = wheel_paths[0]
         assert (
@@ -46,7 +45,7 @@
                     if ext == ".so":
                         # Also remove extra metadata that is embeded as part of
                         # the file name as an extra extension.
-                        ext = ''.join(pathlib.Path(path).suffixes)
+                        ext = "".join(pathlib.Path(path).suffixes)
                     module = path[: -len(ext)].replace("/", ".")
                     mapping[module] = wheel["name"]
         return mapping
@@ -77,4 +76,4 @@
 if __name__ == "__main__":
     wheels = sys.argv[1:]
     generator = Generator(sys.stdout, sys.stderr)
-    exit(generator.run(wheels))
\ No newline at end of file
+    exit(generator.run(wheels))

diff --git a/gazelle/parse.py b/gazelle/parse.py
index bbc9e97..6fe2dc4 100644
--- a/gazelle/parse.py
+++ b/gazelle/parse.py

@@ -60,4 +60,4 @@
 
 
 if __name__ == "__main__":
-    exit(main(sys.stdin, sys.stdout))
\ No newline at end of file
+    exit(main(sys.stdin, sys.stdout))

diff --git a/gazelle/std_modules.py b/gazelle/std_modules.py
index 59e132d..ccd1dcd 100644
--- a/gazelle/std_modules.py
+++ b/gazelle/std_modules.py

@@ -9,11 +9,12 @@
 
 # Don't return any paths, all userland site-packages should be ignored.
 def __override_getusersitepackages__():
-    return ''
+    return ""
 
 
 site.getusersitepackages = __override_getusersitepackages__
 
+
 def is_std_modules(module):
     try:
         __import__(module, globals(), locals(), [], 0)

diff --git a/gazelle/testdata/first_party_file_and_directory_modules/__main__.py b/gazelle/testdata/first_party_file_and_directory_modules/__main__.py
index 6aca4f0..acf5f10 100644
--- a/gazelle/testdata/first_party_file_and_directory_modules/__main__.py
+++ b/gazelle/testdata/first_party_file_and_directory_modules/__main__.py

@@ -4,8 +4,8 @@
 from one.two import two
 from package1.subpackage1.module1 import find_me
 
-assert not hasattr(foo, 'foo')
-assert baz() == 'baz from foo/bar.py'
-assert another_baz() == 'baz from baz.py'
-assert two() == 'two'
-assert find_me() == 'found'
+assert not hasattr(foo, "foo")
+assert baz() == "baz from foo/bar.py"
+assert another_baz() == "baz from baz.py"
+assert two() == "two"
+assert find_me() == "found"

diff --git a/gazelle/testdata/first_party_file_and_directory_modules/baz.py b/gazelle/testdata/first_party_file_and_directory_modules/baz.py
index cc29925..b161d6a 100644
--- a/gazelle/testdata/first_party_file_and_directory_modules/baz.py
+++ b/gazelle/testdata/first_party_file_and_directory_modules/baz.py

@@ -1,2 +1,2 @@
 def baz():
-    return 'baz from baz.py'
+    return "baz from baz.py"

diff --git a/gazelle/testdata/first_party_file_and_directory_modules/foo.py b/gazelle/testdata/first_party_file_and_directory_modules/foo.py
index 81d3ef1..af3cbda 100644
--- a/gazelle/testdata/first_party_file_and_directory_modules/foo.py
+++ b/gazelle/testdata/first_party_file_and_directory_modules/foo.py

@@ -1,2 +1,2 @@
 def foo():
-    print('foo')
+    print("foo")

diff --git a/gazelle/testdata/first_party_file_and_directory_modules/foo/bar.py b/gazelle/testdata/first_party_file_and_directory_modules/foo/bar.py
index 4b6419f..d6524cc 100644
--- a/gazelle/testdata/first_party_file_and_directory_modules/foo/bar.py
+++ b/gazelle/testdata/first_party_file_and_directory_modules/foo/bar.py

@@ -4,4 +4,4 @@
 
 
 def baz():
-    return 'baz from foo/bar.py'
+    return "baz from foo/bar.py"

diff --git a/gazelle/testdata/first_party_file_and_directory_modules/one/two.py b/gazelle/testdata/first_party_file_and_directory_modules/one/two.py
index ce53b87..0020c44 100644
--- a/gazelle/testdata/first_party_file_and_directory_modules/one/two.py
+++ b/gazelle/testdata/first_party_file_and_directory_modules/one/two.py

@@ -1,2 +1,2 @@
 def two():
-    return 'two'
+    return "two"

diff --git a/gazelle/testdata/first_party_file_and_directory_modules/undiscoverable/package1/subpackage1/module1.py b/gazelle/testdata/first_party_file_and_directory_modules/undiscoverable/package1/subpackage1/module1.py
index 668c700..0ff1c42 100644
--- a/gazelle/testdata/first_party_file_and_directory_modules/undiscoverable/package1/subpackage1/module1.py
+++ b/gazelle/testdata/first_party_file_and_directory_modules/undiscoverable/package1/subpackage1/module1.py

@@ -1,2 +1,2 @@
 def find_me():
-    return 'found'
+    return "found"

diff --git a/gazelle/testdata/generated_test_entrypoint/foo.py b/gazelle/testdata/generated_test_entrypoint/foo.py
index a266b7c..cf68624 100644
--- a/gazelle/testdata/generated_test_entrypoint/foo.py
+++ b/gazelle/testdata/generated_test_entrypoint/foo.py

@@ -1,2 +1,2 @@
 def foo():
-    return 'foo'
+    return "foo"

diff --git a/gazelle/testdata/simple_test/foo.py b/gazelle/testdata/simple_test/foo.py
index a266b7c..cf68624 100644
--- a/gazelle/testdata/simple_test/foo.py
+++ b/gazelle/testdata/simple_test/foo.py

@@ -1,2 +1,2 @@
 def foo():
-    return 'foo'
+    return "foo"

diff --git a/python/pip_install/extract_wheels/__init__.py b/python/pip_install/extract_wheels/__init__.py
index bf5a18c..e8097e1 100644
--- a/python/pip_install/extract_wheels/__init__.py
+++ b/python/pip_install/extract_wheels/__init__.py

@@ -7,13 +7,13 @@
 """
 import argparse
 import glob
+import json
 import os
 import pathlib
 import subprocess
 import sys
-import json
 
-from python.pip_install.extract_wheels.lib import bazel, requirements, arguments
+from python.pip_install.extract_wheels.lib import arguments, bazel, requirements
 
 
 def configure_reproducible_wheels() -> None:
@@ -68,18 +68,23 @@
     # relative requirements to be correctly resolved. The --wheel-dir is therefore required to be repointed back to the
     # current calling working directory (the repo root in .../external/name), where the wheel files should be written to
     pip_args = (
-        [sys.executable, "-m", "pip"] +
-        (["--isolated"] if args.isolated else []) +
-        ["wheel", "-r", args.requirements] +
-        ["--wheel-dir", os.getcwd()] +
-        deserialized_args["extra_pip_args"]
+        [sys.executable, "-m", "pip"]
+        + (["--isolated"] if args.isolated else [])
+        + ["wheel", "-r", args.requirements]
+        + ["--wheel-dir", os.getcwd()]
+        + deserialized_args["extra_pip_args"]
     )
 
     env = os.environ.copy()
     env.update(deserialized_args["environment"])
 
     # Assumes any errors are logged by pip so do nothing. This command will fail if pip fails
-    subprocess.run(pip_args, check=True, env=env, cwd=str(pathlib.Path(args.requirements).parent.resolve()))
+    subprocess.run(
+        pip_args,
+        check=True,
+        env=env,
+        cwd=str(pathlib.Path(args.requirements).parent.resolve()),
+    )
 
     extras = requirements.parse_extras(args.requirements)
 

diff --git a/python/pip_install/extract_wheels/lib/arguments.py b/python/pip_install/extract_wheels/lib/arguments.py
index 9c8f49a..d7d3452 100644
--- a/python/pip_install/extract_wheels/lib/arguments.py
+++ b/python/pip_install/extract_wheels/lib/arguments.py

@@ -10,10 +10,14 @@
         help="The external repo name to install dependencies. In the format '@{REPO_NAME}'",
     )
     parser.add_argument(
-        "--isolated", action="store_true", help="Whether or not to include the `--isolated` pip flag.",
+        "--isolated",
+        action="store_true",
+        help="Whether or not to include the `--isolated` pip flag.",
     )
     parser.add_argument(
-        "--extra_pip_args", action="store", help="Extra arguments to pass down to pip.",
+        "--extra_pip_args",
+        action="store",
+        help="Extra arguments to pass down to pip.",
     )
     parser.add_argument(
         "--pip_data_exclude",

diff --git a/python/pip_install/extract_wheels/lib/arguments_test.py b/python/pip_install/extract_wheels/lib/arguments_test.py
index 89ab291..6a714be 100644
--- a/python/pip_install/extract_wheels/lib/arguments_test.py
+++ b/python/pip_install/extract_wheels/lib/arguments_test.py

@@ -13,15 +13,17 @@
         repo_prefix = "pypi_"
         index_url = "--index_url=pypi.org/simple"
         extra_pip_args = [index_url]
-        args_dict = vars(parser.parse_args(
-            args=[
-                "--repo",
-                repo_name,
-                f"--extra_pip_args={json.dumps({'arg': extra_pip_args})}",
-                "--repo-prefix",
-                repo_prefix,
-            ]
-        ))
+        args_dict = vars(
+            parser.parse_args(
+                args=[
+                    "--repo",
+                    repo_name,
+                    f"--extra_pip_args={json.dumps({'arg': extra_pip_args})}",
+                    "--repo-prefix",
+                    repo_prefix,
+                ]
+            )
+        )
         args_dict = arguments.deserialize_structured_args(args_dict)
         self.assertIn("repo", args_dict)
         self.assertIn("extra_pip_args", args_dict)

diff --git a/python/pip_install/extract_wheels/lib/bazel.py b/python/pip_install/extract_wheels/lib/bazel.py
index 3411756..8e9519f 100644
--- a/python/pip_install/extract_wheels/lib/bazel.py
+++ b/python/pip_install/extract_wheels/lib/bazel.py

@@ -1,13 +1,12 @@
 """Utility functions to manipulate Bazel files"""
-import os
-import textwrap
 import json
-from typing import Iterable, List, Dict, Set, Optional
+import os
 import shutil
+import textwrap
 from pathlib import Path
+from typing import Dict, Iterable, List, Optional, Set
 
-from python.pip_install.extract_wheels.lib import namespace_pkgs, wheel, purelib
-
+from python.pip_install.extract_wheels.lib import namespace_pkgs, purelib, wheel
 
 WHEEL_FILE_LABEL = "whl"
 PY_LIBRARY_LABEL = "pkg"
@@ -16,7 +15,9 @@
 WHEEL_ENTRY_POINT_PREFIX = "rules_python_wheel_entry_point"
 
 
-def generate_entry_point_contents(entry_point: str, shebang: str = "#!/usr/bin/env python3") -> str:
+def generate_entry_point_contents(
+    entry_point: str, shebang: str = "#!/usr/bin/env python3"
+) -> str:
     """Generate the contents of an entry point script.
 
     Args:
@@ -29,7 +30,8 @@
         str: A string of python code.
     """
     module, method = entry_point.split(":", 1)
-    return textwrap.dedent("""\
+    return textwrap.dedent(
+        """\
         {shebang}
         import sys
         from {module} import {method}
@@ -37,10 +39,9 @@
             rc = {method}()
             sys.exit({method}())
         """.format(
-        shebang=shebang,
-        module=module,
-        method=method
-    ))
+            shebang=shebang, module=module, method=method
+        )
+    )
 
 
 def generate_entry_point_rule(script: str, pkg: str) -> str:
@@ -60,7 +61,8 @@
         str: A `py_binary` instantiation.
     """
     name = os.path.splitext(script)[0]
-    return textwrap.dedent("""\
+    return textwrap.dedent(
+        """\
         py_binary(
             name = "{name}",
             srcs = ["{src}"],
@@ -70,10 +72,9 @@
             deps = ["{pkg}"],
         )
         """.format(
-        name=name,
-        src=str(script).replace("\\", "/"),
-        pkg=pkg
-    ))
+            name=name, src=str(script).replace("\\", "/"), pkg=pkg
+        )
+    )
 
 
 def generate_build_file_contents(
@@ -112,8 +113,10 @@
         "WORKSPACE",
     ] + pip_data_exclude
 
-    return "\n".join([textwrap.dedent(
-        """\
+    return "\n".join(
+        [
+            textwrap.dedent(
+                """\
         load("@rules_python//python:defs.bzl", "py_library", "py_binary")
 
         package(default_visibility = ["//visibility:public"])
@@ -145,16 +148,19 @@
             tags = [{tags}],
         )
         """.format(
-            name=name,
-            dependencies=",".join(dependencies),
-            data_exclude=json.dumps(data_exclude),
-            whl_file_label=WHEEL_FILE_LABEL,
-            whl_file_deps=",".join(whl_file_deps),
-            tags=",".join(["\"%s\"" % t for t in tags]),
-            data_label=DATA_LABEL,
-            dist_info_label=DIST_INFO_LABEL,
-            entry_point_prefix=WHEEL_ENTRY_POINT_PREFIX,
-        ))] + additional_targets
+                    name=name,
+                    dependencies=",".join(dependencies),
+                    data_exclude=json.dumps(data_exclude),
+                    whl_file_label=WHEEL_FILE_LABEL,
+                    whl_file_deps=",".join(whl_file_deps),
+                    tags=",".join(['"%s"' % t for t in tags]),
+                    data_label=DATA_LABEL,
+                    dist_info_label=DIST_INFO_LABEL,
+                    entry_point_prefix=WHEEL_ENTRY_POINT_PREFIX,
+                )
+            )
+        ]
+        + additional_targets
     )
 
 
@@ -251,7 +257,8 @@
     """
 
     namespace_pkg_dirs = namespace_pkgs.implicit_namespace_packages(
-        wheel_dir, ignored_dirnames=["%s/bin" % wheel_dir],
+        wheel_dir,
+        ignored_dirnames=["%s/bin" % wheel_dir],
     )
 
     for ns_pkg_dir in namespace_pkg_dirs:
@@ -271,11 +278,15 @@
 
 
 def sanitised_repo_library_label(whl_name: str, repo_prefix: str) -> str:
-    return '"{}:{}"'.format(_whl_name_to_repo_root(whl_name, repo_prefix), PY_LIBRARY_LABEL)
+    return '"{}:{}"'.format(
+        _whl_name_to_repo_root(whl_name, repo_prefix), PY_LIBRARY_LABEL
+    )
 
 
 def sanitised_repo_file_label(whl_name: str, repo_prefix: str) -> str:
-    return '"{}:{}"'.format(_whl_name_to_repo_root(whl_name, repo_prefix), WHEEL_FILE_LABEL)
+    return '"{}:{}"'.format(
+        _whl_name_to_repo_root(whl_name, repo_prefix), WHEEL_FILE_LABEL
+    )
 
 
 def extract_wheel(
@@ -335,17 +346,23 @@
             sanitised_file_label(d, prefix=repo_prefix) for d in whl_deps
         ]
 
-    library_name = PY_LIBRARY_LABEL if incremental else sanitise_name(whl.name, repo_prefix)
+    library_name = (
+        PY_LIBRARY_LABEL if incremental else sanitise_name(whl.name, repo_prefix)
+    )
 
     directory_path = Path(directory)
     entry_points = []
     for name, entry_point in sorted(whl.entry_points().items()):
         entry_point_script = f"{WHEEL_ENTRY_POINT_PREFIX}_{name}.py"
-        (directory_path / entry_point_script).write_text(generate_entry_point_contents(entry_point))
-        entry_points.append(generate_entry_point_rule(
-            entry_point_script,
-            library_name,
-        ))
+        (directory_path / entry_point_script).write_text(
+            generate_entry_point_contents(entry_point)
+        )
+        entry_points.append(
+            generate_entry_point_rule(
+                entry_point_script,
+                library_name,
+            )
+        )
 
     with open(os.path.join(directory, "BUILD.bazel"), "w") as build_file:
         contents = generate_build_file_contents(

diff --git a/python/pip_install/extract_wheels/lib/bazel_test.py b/python/pip_install/extract_wheels/lib/bazel_test.py
index 5c22047..c6c11dc 100644
--- a/python/pip_install/extract_wheels/lib/bazel_test.py
+++ b/python/pip_install/extract_wheels/lib/bazel_test.py

@@ -16,7 +16,8 @@
 
     def test_generate_entry_point_contents_with_shebang(self):
         got = generate_entry_point_contents(
-            "sphinx.cmd.build:main", shebang="#!/usr/bin/python")
+            "sphinx.cmd.build:main", shebang="#!/usr/bin/python"
+        )
         want = """#!/usr/bin/python
 import sys
 from sphinx.cmd.build import main

diff --git a/python/pip_install/extract_wheels/lib/namespace_pkgs.py b/python/pip_install/extract_wheels/lib/namespace_pkgs.py
index b3177b3..5ddd4e1 100644
--- a/python/pip_install/extract_wheels/lib/namespace_pkgs.py
+++ b/python/pip_install/extract_wheels/lib/namespace_pkgs.py

@@ -1,8 +1,8 @@
 """Utility functions to discover python package types"""
 import os
-from pathlib import Path  # supported in >= 3.4
 import textwrap
-from typing import Set, List, Optional
+from pathlib import Path  # supported in >= 3.4
+from typing import List, Optional, Set
 
 
 def implicit_namespace_packages(
@@ -25,19 +25,27 @@
     directory_path = Path(directory)
     ignored_dirname_paths: List[Path] = [Path(p) for p in ignored_dirnames or ()]
     # Traverse bottom-up because a directory can be a namespace pkg because its child contains module files.
-    for dirpath, dirnames, filenames in map(lambda t: (Path(t[0]), *t[1:]), os.walk(directory_path, topdown=False)):
+    for dirpath, dirnames, filenames in map(
+        lambda t: (Path(t[0]), *t[1:]), os.walk(directory_path, topdown=False)
+    ):
         if "__init__.py" in filenames:
             standard_pkg_dirs.add(dirpath)
             continue
         elif ignored_dirname_paths:
             is_ignored_dir = dirpath in ignored_dirname_paths
-            child_of_ignored_dir = any(d in dirpath.parents for d in ignored_dirname_paths)
+            child_of_ignored_dir = any(
+                d in dirpath.parents for d in ignored_dirname_paths
+            )
             if is_ignored_dir or child_of_ignored_dir:
                 continue
 
         dir_includes_py_modules = _includes_python_modules(filenames)
-        parent_of_namespace_pkg = any(Path(dirpath, d) in namespace_pkg_dirs for d in dirnames)
-        parent_of_standard_pkg = any(Path(dirpath, d) in standard_pkg_dirs for d in dirnames)
+        parent_of_namespace_pkg = any(
+            Path(dirpath, d) in namespace_pkg_dirs for d in dirnames
+        )
+        parent_of_standard_pkg = any(
+            Path(dirpath, d) in standard_pkg_dirs for d in dirnames
+        )
         parent_of_pkg = parent_of_namespace_pkg or parent_of_standard_pkg
         if (
             (dir_includes_py_modules or parent_of_pkg)
@@ -94,10 +102,6 @@
         ".py",  # Source modules
         ".pyc",  # Compiled bytecode modules
         ".so",  # Unix extension modules
-        ".pyd"  # https://docs.python.org/3/faq/windows.html#is-a-pyd-file-the-same-as-a-dll
+        ".pyd",  # https://docs.python.org/3/faq/windows.html#is-a-pyd-file-the-same-as-a-dll
     }
-    return any(
-        Path(f).suffix in module_suffixes
-        for f
-        in files
-    )
+    return any(Path(f).suffix in module_suffixes for f in files)

diff --git a/python/pip_install/extract_wheels/lib/namespace_pkgs_test.py b/python/pip_install/extract_wheels/lib/namespace_pkgs_test.py
index dca7026..815fe62 100644
--- a/python/pip_install/extract_wheels/lib/namespace_pkgs_test.py
+++ b/python/pip_install/extract_wheels/lib/namespace_pkgs_test.py

@@ -2,8 +2,8 @@
 import pathlib
 import shutil
 import tempfile
-from typing import Optional, Set
 import unittest
+from typing import Optional, Set
 
 from python.pip_install.extract_wheels.lib import namespace_pkgs
 
@@ -33,7 +33,6 @@
 
 
 class TestImplicitNamespacePackages(unittest.TestCase):
-
     def assertPathsEqual(self, actual: Set[pathlib.Path], expected: Set[str]) -> None:
         self.assertEqual(actual, {pathlib.Path(p) for p in expected})
 

diff --git a/python/pip_install/extract_wheels/lib/purelib.py b/python/pip_install/extract_wheels/lib/purelib.py
index 99e2c80..40eb25d 100644
--- a/python/pip_install/extract_wheels/lib/purelib.py
+++ b/python/pip_install/extract_wheels/lib/purelib.py

@@ -48,5 +48,6 @@
         # See: https://github.com/dillon-giacoppo/rules_python_external/issues/8
         if not pathlib.Path(root_dir, grandchild.name).exists():
             shutil.move(
-                src=str(grandchild), dst=root_dir,
+                src=str(grandchild),
+                dst=root_dir,
             )

diff --git a/python/pip_install/extract_wheels/lib/requirements.py b/python/pip_install/extract_wheels/lib/requirements.py
index e246379..cfab339 100644
--- a/python/pip_install/extract_wheels/lib/requirements.py
+++ b/python/pip_install/extract_wheels/lib/requirements.py

@@ -1,5 +1,5 @@
 import re
-from typing import Dict, Set, Tuple, Optional
+from typing import Dict, Optional, Set, Tuple
 
 
 def parse_extras(requirements_path: str) -> Dict[str, Set[str]]:

diff --git a/python/pip_install/extract_wheels/lib/requirements_bzl_test.py b/python/pip_install/extract_wheels/lib/requirements_bzl_test.py
index 3424f3e..d753f6f 100644
--- a/python/pip_install/extract_wheels/lib/requirements_bzl_test.py
+++ b/python/pip_install/extract_wheels/lib/requirements_bzl_test.py

@@ -6,10 +6,12 @@
 class TestGenerateRequirementsFileContents(unittest.TestCase):
     def test_all_wheel_requirements(self) -> None:
         contents = bazel.generate_requirements_file_contents(
-            repo_name='test',
+            repo_name="test",
             targets=['"@test//pypi__pkg1"', '"@test//pypi__pkg2"'],
         )
-        expected = 'all_whl_requirements = ["@test//pypi__pkg1:whl","@test//pypi__pkg2:whl"]'
+        expected = (
+            'all_whl_requirements = ["@test//pypi__pkg1:whl","@test//pypi__pkg2:whl"]'
+        )
         self.assertIn(expected, contents)
 
 

diff --git a/python/pip_install/extract_wheels/lib/requirements_test.py b/python/pip_install/extract_wheels/lib/requirements_test.py
index ba7ee13..0ee4255 100644
--- a/python/pip_install/extract_wheels/lib/requirements_test.py
+++ b/python/pip_install/extract_wheels/lib/requirements_test.py

@@ -17,8 +17,14 @@
                 "name[quux, strange];python_version<'2.7' and platform_version=='2'",
                 ("name", frozenset(["quux", "strange"])),
             ),
-            ("name; (os_name=='a' or os_name=='b') and os_name=='c'", (None, None),),
-            ("name@http://foo.com", (None, None),),
+            (
+                "name; (os_name=='a' or os_name=='b') and os_name=='c'",
+                (None, None),
+            ),
+            (
+                "name@http://foo.com",
+                (None, None),
+            ),
         ]
 
         for case, expected in cases:

diff --git a/python/pip_install/extract_wheels/lib/wheel.py b/python/pip_install/extract_wheels/lib/wheel.py
index a60efc6..fadf8af 100644
--- a/python/pip_install/extract_wheels/lib/wheel.py
+++ b/python/pip_install/extract_wheels/lib/wheel.py

@@ -55,7 +55,9 @@
             # Calculate the location of the entry_points.txt file
             metadata = self.metadata
             name = "{}-{}".format(metadata.name.replace("-", "_"), metadata.version)
-            entry_points_path = os.path.join("{}.dist-info".format(name), "entry_points.txt")
+            entry_points_path = os.path.join(
+                "{}.dist-info".format(name), "entry_points.txt"
+            )
 
             # If this file does not exist in the wheel, there are no entry points
             if entry_points_path not in whl.namelist():
@@ -111,7 +113,7 @@
 
 
 def get_dist_info(wheel_dir: str) -> str:
-    """"Returns the relative path to the dist-info directory if it exists.
+    """ "Returns the relative path to the dist-info directory if it exists.
 
     Args:
          wheel_dir: The root of the extracted wheel directory.

diff --git a/python/pip_install/extract_wheels/lib/whl_filegroup_test.py b/python/pip_install/extract_wheels/lib/whl_filegroup_test.py
index 39a0d4c..5bf5f7a 100644
--- a/python/pip_install/extract_wheels/lib/whl_filegroup_test.py
+++ b/python/pip_install/extract_wheels/lib/whl_filegroup_test.py

@@ -1,7 +1,6 @@
 import os
 import shutil
 import tempfile
-from typing import Optional
 import unittest
 
 from python.pip_install.extract_wheels.lib import bazel
@@ -12,9 +11,7 @@
         self.wheel_name = "example_minimal_package-0.0.1-py3-none-any.whl"
         self.wheel_dir = tempfile.mkdtemp()
         self.wheel_path = os.path.join(self.wheel_dir, self.wheel_name)
-        shutil.copy(
-            os.path.join("examples", "wheel", self.wheel_name), self.wheel_dir
-        )
+        shutil.copy(os.path.join("examples", "wheel", self.wheel_name), self.wheel_dir)
         self.original_dir = os.getcwd()
         os.chdir(self.wheel_dir)
 
@@ -33,15 +30,17 @@
             pip_data_exclude=[],
             enable_implicit_namespace_pkgs=False,
             incremental=incremental,
-            repo_prefix=repo_prefix
+            repo_prefix=repo_prefix,
         )
         # Take off the leading // from the returned label.
         # Assert that the raw wheel ends up in the package.
-        generated_bazel_dir = generated_bazel_dir[2:] if not incremental else self.wheel_dir
+        generated_bazel_dir = (
+            generated_bazel_dir[2:] if not incremental else self.wheel_dir
+        )
         self.assertIn(self.wheel_name, os.listdir(generated_bazel_dir))
         with open("{}/BUILD.bazel".format(generated_bazel_dir)) as build_file:
             build_file_content = build_file.read()
-            self.assertIn('filegroup', build_file_content)
+            self.assertIn("filegroup", build_file_content)
 
     def test_nonincremental(self) -> None:
         self._run(repo_prefix="prefix_")

diff --git a/python/pip_install/parse_requirements_to_bzl/__init__.py b/python/pip_install/parse_requirements_to_bzl/__init__.py
index e22d4a3..1e1261d 100644
--- a/python/pip_install/parse_requirements_to_bzl/__init__.py
+++ b/python/pip_install/parse_requirements_to_bzl/__init__.py

@@ -1,18 +1,27 @@
 import argparse
 import json
-import textwrap
-import sys
 import shlex
+import sys
+import textwrap
 from typing import List, Tuple
 
-from python.pip_install.extract_wheels.lib import bazel, arguments
-from pip._internal.req import parse_requirements, constructors
-from pip._internal.req.req_install import InstallRequirement
-from pip._internal.req.req_file import get_file_content, preprocess, handle_line, get_line_parser, RequirementsFileParser
 from pip._internal.network.session import PipSession
+from pip._internal.req import constructors, parse_requirements
+from pip._internal.req.req_file import (
+    RequirementsFileParser,
+    get_file_content,
+    get_line_parser,
+    handle_line,
+    preprocess,
+)
+from pip._internal.req.req_install import InstallRequirement
+
+from python.pip_install.extract_wheels.lib import arguments, bazel
 
 
-def parse_install_requirements(requirements_lock: str, extra_pip_args: List[str]) -> List[Tuple[InstallRequirement, str]]:
+def parse_install_requirements(
+    requirements_lock: str, extra_pip_args: List[str]
+) -> List[Tuple[InstallRequirement, str]]:
     ps = PipSession()
     # This is roughly taken from pip._internal.req.req_file.parse_requirements
     # (https://github.com/pypa/pip/blob/21.0.1/src/pip/_internal/req/req_file.py#L127) in order to keep
@@ -22,13 +31,12 @@
     parser = RequirementsFileParser(ps, line_parser)
     install_req_and_lines: List[Tuple[InstallRequirement, str]] = []
     _, content = get_file_content(requirements_lock, ps)
-    for parsed_line, (_, line) in zip(parser.parse(requirements_lock, constraint=False), preprocess(content)):
+    for parsed_line, (_, line) in zip(
+        parser.parse(requirements_lock, constraint=False), preprocess(content)
+    ):
         if parsed_line.is_requirement:
             install_req_and_lines.append(
-                (
-                    constructors.install_req_from_line(parsed_line.requirement),
-                    line
-                )
+                (constructors.install_req_from_line(parsed_line.requirement), line)
             )
 
         else:
@@ -36,7 +44,9 @@
     return install_req_and_lines
 
 
-def repo_names_and_requirements(install_reqs: List[Tuple[InstallRequirement, str]], repo_prefix: str) -> List[Tuple[str, str]]:
+def repo_names_and_requirements(
+    install_reqs: List[Tuple[InstallRequirement, str]], repo_prefix: str
+) -> List[Tuple[str, str]]:
     return [
         (
             bazel.sanitise_name(ir.name, prefix=repo_prefix),
@@ -61,19 +71,26 @@
     # Pop this off because it wont be used as a config argument to the whl_library rule.
     requirements_lock = args.pop("requirements_lock")
 
-    install_req_and_lines = parse_install_requirements(requirements_lock, args["extra_pip_args"])
+    install_req_and_lines = parse_install_requirements(
+        requirements_lock, args["extra_pip_args"]
+    )
     repo_names_and_reqs = repo_names_and_requirements(
         install_req_and_lines, args["repo_prefix"]
     )
-    all_requirements = ", ".join([
-        bazel.sanitised_repo_library_label(ir.name, repo_prefix=args["repo_prefix"])
-        for ir, _ in install_req_and_lines
-    ])
-    all_whl_requirements = ", ".join([
-        bazel.sanitised_repo_file_label(ir.name, repo_prefix=args["repo_prefix"])
-        for ir, _ in install_req_and_lines
-    ])
-    return textwrap.dedent("""\
+    all_requirements = ", ".join(
+        [
+            bazel.sanitised_repo_library_label(ir.name, repo_prefix=args["repo_prefix"])
+            for ir, _ in install_req_and_lines
+        ]
+    )
+    all_whl_requirements = ", ".join(
+        [
+            bazel.sanitised_repo_file_label(ir.name, repo_prefix=args["repo_prefix"])
+            for ir, _ in install_req_and_lines
+        ]
+    )
+    return textwrap.dedent(
+        """\
         load("@rules_python//python/pip_install:pip_repository.bzl", "whl_library")
 
         all_requirements = [{all_requirements}]
@@ -121,11 +138,13 @@
             data_label=bazel.DATA_LABEL,
             dist_info_label=bazel.DIST_INFO_LABEL,
             entry_point_prefix=bazel.WHEEL_ENTRY_POINT_PREFIX,
-            )
         )
+    )
+
 
 def coerce_to_bool(option):
-    return str(option).lower() == 'true'
+    return str(option).lower() == "true"
+
 
 def main() -> None:
     parser = argparse.ArgumentParser(
@@ -166,6 +185,4 @@
     args = parser.parse_args()
 
     with open("requirements.bzl", "w") as requirement_file:
-        requirement_file.write(
-            generate_parsed_requirements_contents(args)
-        )
+        requirement_file.write(generate_parsed_requirements_contents(args))

diff --git a/python/pip_install/parse_requirements_to_bzl/extract_single_wheel/__init__.py b/python/pip_install/parse_requirements_to_bzl/extract_single_wheel/__init__.py
index 3937116..2c03ff3 100644
--- a/python/pip_install/parse_requirements_to_bzl/extract_single_wheel/__init__.py
+++ b/python/pip_install/parse_requirements_to_bzl/extract_single_wheel/__init__.py

@@ -1,14 +1,13 @@
-import os
 import argparse
-import sys
+import errno
 import glob
+import os
 import subprocess
-import json
-
+import sys
 from tempfile import NamedTemporaryFile
 
-from python.pip_install.extract_wheels.lib import bazel, requirements, arguments
 from python.pip_install.extract_wheels import configure_reproducible_wheels
+from python.pip_install.extract_wheels.lib import arguments, bazel, requirements
 
 
 def main() -> None:
@@ -29,13 +28,13 @@
     configure_reproducible_wheels()
 
     pip_args = (
-        [sys.executable, "-m", "pip"] +
-        (["--isolated"] if args.isolated else []) +
-        ["wheel", "--no-deps"] +
-        deserialized_args["extra_pip_args"]
+        [sys.executable, "-m", "pip"]
+        + (["--isolated"] if args.isolated else [])
+        + ["wheel", "--no-deps"]
+        + deserialized_args["extra_pip_args"]
     )
 
-    requirement_file = NamedTemporaryFile(mode='wb', delete=False)
+    requirement_file = NamedTemporaryFile(mode="wb", delete=False)
     try:
         requirement_file.write(args.requirement.encode("utf-8"))
         requirement_file.flush()

diff --git a/python/pip_install/parse_requirements_to_bzl/parse_requirements_to_bzl_test.py b/python/pip_install/parse_requirements_to_bzl/parse_requirements_to_bzl_test.py
index ad603f4..a5c76d3 100644
--- a/python/pip_install/parse_requirements_to_bzl/parse_requirements_to_bzl_test.py
+++ b/python/pip_install/parse_requirements_to_bzl/parse_requirements_to_bzl_test.py

@@ -1,22 +1,21 @@
-import unittest
 import argparse
 import json
+import unittest
 from tempfile import NamedTemporaryFile
 
-from python.pip_install.parse_requirements_to_bzl import generate_parsed_requirements_contents
-from python.pip_install.extract_wheels.lib.bazel import (
-    sanitised_repo_library_label,
-    sanitised_repo_file_label
+from python.pip_install.parse_requirements_to_bzl import (
+    generate_parsed_requirements_contents,
 )
 
 
 class TestParseRequirementsToBzl(unittest.TestCase):
-
     def test_generated_requirements_bzl(self) -> None:
         with NamedTemporaryFile() as requirements_lock:
             comments_and_flags = "#comment\n--require-hashes True\n"
             requirement_string = "foo==0.0.0 --hash=sha256:hashofFoowhl"
-            requirements_lock.write(bytes(comments_and_flags + requirement_string, encoding="utf-8"))
+            requirements_lock.write(
+                bytes(comments_and_flags + requirement_string, encoding="utf-8")
+            )
             requirements_lock.flush()
             args = argparse.Namespace()
             args.requirements_lock = requirements_lock.name
@@ -24,23 +23,37 @@
             extra_pip_args = ["--index-url=pypi.org/simple"]
             pip_data_exclude = ["**.foo"]
             args.extra_pip_args = json.dumps({"arg": extra_pip_args})
-            args.pip_data_exclude= json.dumps({"arg": pip_data_exclude})
+            args.pip_data_exclude = json.dumps({"arg": pip_data_exclude})
             args.python_interpreter = "/custom/python3"
             args.python_interpreter_target = "@custom_python//:exec"
-            args.environment= json.dumps({"arg": {}})
+            args.environment = json.dumps({"arg": {}})
             contents = generate_parsed_requirements_contents(args)
             library_target = "@pip_parsed_deps_pypi__foo//:pkg"
             whl_target = "@pip_parsed_deps_pypi__foo//:whl"
-            all_requirements = 'all_requirements = ["{library_target}"]'.format(library_target=library_target)
-            all_whl_requirements = 'all_whl_requirements = ["{whl_target}"]'.format(whl_target=whl_target)
+            all_requirements = 'all_requirements = ["{library_target}"]'.format(
+                library_target=library_target
+            )
+            all_whl_requirements = 'all_whl_requirements = ["{whl_target}"]'.format(
+                whl_target=whl_target
+            )
             self.assertIn(all_requirements, contents, contents)
             self.assertIn(all_whl_requirements, contents, contents)
             self.assertIn(requirement_string, contents, contents)
             all_flags = extra_pip_args + ["--require-hashes", "True"]
-            self.assertIn("'extra_pip_args': {}".format(repr(all_flags)), contents, contents)
-            self.assertIn("'pip_data_exclude': {}".format(repr(pip_data_exclude)), contents, contents)
+            self.assertIn(
+                "'extra_pip_args': {}".format(repr(all_flags)), contents, contents
+            )
+            self.assertIn(
+                "'pip_data_exclude': {}".format(repr(pip_data_exclude)),
+                contents,
+                contents,
+            )
             self.assertIn("'python_interpreter': '/custom/python3'", contents, contents)
-            self.assertIn("'python_interpreter_target': '@custom_python//:exec'", contents, contents)
+            self.assertIn(
+                "'python_interpreter_target': '@custom_python//:exec'",
+                contents,
+                contents,
+            )
             # Assert it gets set to an empty dict by default.
             self.assertIn("'environment': {}", contents, contents)
 

diff --git a/python/pip_install/pip_compile.py b/python/pip_install/pip_compile.py
index ce40285..1e789e9 100644
--- a/python/pip_install/pip_compile.py
+++ b/python/pip_install/pip_compile.py

@@ -49,7 +49,7 @@
     #
     # Changing to the WORKSPACE root avoids 'file not found' errors when the `.update` target is run
     # from different directories within the WORKSPACE.
-    os.chdir(os.environ['BUILD_WORKSPACE_DIRECTORY'])
+    os.chdir(os.environ["BUILD_WORKSPACE_DIRECTORY"])
 else:
     err_msg = (
         "Expected to find BUILD_WORKSPACE_DIRECTORY (running under `bazel run`) or "
@@ -61,11 +61,14 @@
     )
     sys.exit(1)
 
-update_target_pkg = "/".join(requirements_in.split('/')[:-1])
+update_target_pkg = "/".join(requirements_in.split("/")[:-1])
 # $(rootpath) in the workspace root gives ./requirements.in
 if update_target_pkg == ".":
     update_target_pkg = ""
-update_command = os.getenv("CUSTOM_COMPILE_COMMAND") or "bazel run //%s:%s" % (update_target_pkg, update_target_name)
+update_command = os.getenv("CUSTOM_COMPILE_COMMAND") or "bazel run //%s:%s" % (
+    update_target_pkg,
+    update_target_name,
+)
 
 os.environ["CUSTOM_COMPILE_COMMAND"] = update_command
 os.environ["PIP_CONFIG_FILE"] = os.getenv("PIP_CONFIG_FILE") or os.devnull
@@ -100,18 +103,15 @@
             if golden != out:
                 import difflib
 
-                print(''.join(difflib.unified_diff(golden, out)), file=sys.stderr)
+                print("".join(difflib.unified_diff(golden, out)), file=sys.stderr)
                 print(
-                    "Lock file out of date. Run '"
-                    + update_command
-                    + "' to update.",
+                    "Lock file out of date. Run '" + update_command + "' to update.",
                     file=sys.stderr,
                 )
                 sys.exit(1)
             sys.exit(0)
         else:
             print(
-                f"pip-compile unexpectedly exited with code {e.code}.",
-                file=sys.stderr
+                f"pip-compile unexpectedly exited with code {e.code}.", file=sys.stderr
             )
             sys.exit(1)

diff --git a/python/runfiles/runfiles.py b/python/runfiles/runfiles.py
index e8e867d..f11613d 100644
--- a/python/runfiles/runfiles.py
+++ b/python/runfiles/runfiles.py

@@ -70,224 +70,231 @@
 
 
 def CreateManifestBased(manifest_path):
-  return _Runfiles(_ManifestBased(manifest_path))
+    return _Runfiles(_ManifestBased(manifest_path))
 
 
 def CreateDirectoryBased(runfiles_dir_path):
-  return _Runfiles(_DirectoryBased(runfiles_dir_path))
+    return _Runfiles(_DirectoryBased(runfiles_dir_path))
 
 
 def Create(env=None):
-  """Returns a new `Runfiles` instance.
+    """Returns a new `Runfiles` instance.
 
-  The returned object is either:
-  - manifest-based, meaning it looks up runfile paths from a manifest file, or
-  - directory-based, meaning it looks up runfile paths under a given directory
-    path
+    The returned object is either:
+    - manifest-based, meaning it looks up runfile paths from a manifest file, or
+    - directory-based, meaning it looks up runfile paths under a given directory
+      path
 
-  If `env` contains "RUNFILES_MANIFEST_FILE" with non-empty value, this method
-  returns a manifest-based implementation. The object eagerly reads and caches
-  the whole manifest file upon instantiation; this may be relevant for
-  performance consideration.
+    If `env` contains "RUNFILES_MANIFEST_FILE" with non-empty value, this method
+    returns a manifest-based implementation. The object eagerly reads and caches
+    the whole manifest file upon instantiation; this may be relevant for
+    performance consideration.
 
-  Otherwise, if `env` contains "RUNFILES_DIR" with non-empty value (checked in
-  this priority order), this method returns a directory-based implementation.
+    Otherwise, if `env` contains "RUNFILES_DIR" with non-empty value (checked in
+    this priority order), this method returns a directory-based implementation.
 
-  If neither cases apply, this method returns null.
+    If neither cases apply, this method returns null.
 
-  Args:
-    env: {string: string}; optional; the map of environment variables. If None,
-        this function uses the environment variable map of this process.
-  Raises:
-    IOError: if some IO error occurs.
-  """
-  env_map = os.environ if env is None else env
-  manifest = env_map.get("RUNFILES_MANIFEST_FILE")
-  if manifest:
-    return CreateManifestBased(manifest)
+    Args:
+      env: {string: string}; optional; the map of environment variables. If None,
+          this function uses the environment variable map of this process.
+    Raises:
+      IOError: if some IO error occurs.
+    """
+    env_map = os.environ if env is None else env
+    manifest = env_map.get("RUNFILES_MANIFEST_FILE")
+    if manifest:
+        return CreateManifestBased(manifest)
 
-  directory = env_map.get("RUNFILES_DIR")
-  if directory:
-    return CreateDirectoryBased(directory)
+    directory = env_map.get("RUNFILES_DIR")
+    if directory:
+        return CreateDirectoryBased(directory)
 
-  return None
+    return None
 
 
 class _Runfiles(object):
-  """Returns the runtime location of runfiles.
-
-  Runfiles are data-dependencies of Bazel-built binaries and tests.
-  """
-
-  def __init__(self, strategy):
-    self._strategy = strategy
-
-  def Rlocation(self, path):
-    """Returns the runtime path of a runfile.
+    """Returns the runtime location of runfiles.
 
     Runfiles are data-dependencies of Bazel-built binaries and tests.
-
-    The returned path may not be valid. The caller should check the path's
-    validity and that the path exists.
-
-    The function may return None. In that case the caller can be sure that the
-    rule does not know about this data-dependency.
-
-    Args:
-      path: string; runfiles-root-relative path of the runfile
-    Returns:
-      the path to the runfile, which the caller should check for existence, or
-      None if the method doesn't know about this runfile
-    Raises:
-      TypeError: if `path` is not a string
-      ValueError: if `path` is None or empty, or it's absolute or not normalized
     """
-    if not path:
-      raise ValueError()
-    if not isinstance(path, str):
-      raise TypeError()
-    if (path.startswith("../") or "/.." in path or path.startswith("./") or
-        "/./" in path or path.endswith("/.") or "//" in path):
-      raise ValueError("path is not normalized: \"%s\"" % path)
-    if path[0] == "\\":
-      raise ValueError("path is absolute without a drive letter: \"%s\"" % path)
-    if os.path.isabs(path):
-      return path
-    return self._strategy.RlocationChecked(path)
 
-  def EnvVars(self):
-    """Returns environment variables for subprocesses.
+    def __init__(self, strategy):
+        self._strategy = strategy
 
-    The caller should set the returned key-value pairs in the environment of
-    subprocesses in case those subprocesses are also Bazel-built binaries that
-    need to use runfiles.
+    def Rlocation(self, path):
+        """Returns the runtime path of a runfile.
 
-    Returns:
-      {string: string}; a dict; keys are environment variable names, values are
-      the values for these environment variables
-    """
-    return self._strategy.EnvVars()
+        Runfiles are data-dependencies of Bazel-built binaries and tests.
+
+        The returned path may not be valid. The caller should check the path's
+        validity and that the path exists.
+
+        The function may return None. In that case the caller can be sure that the
+        rule does not know about this data-dependency.
+
+        Args:
+          path: string; runfiles-root-relative path of the runfile
+        Returns:
+          the path to the runfile, which the caller should check for existence, or
+          None if the method doesn't know about this runfile
+        Raises:
+          TypeError: if `path` is not a string
+          ValueError: if `path` is None or empty, or it's absolute or not normalized
+        """
+        if not path:
+            raise ValueError()
+        if not isinstance(path, str):
+            raise TypeError()
+        if (
+            path.startswith("../")
+            or "/.." in path
+            or path.startswith("./")
+            or "/./" in path
+            or path.endswith("/.")
+            or "//" in path
+        ):
+            raise ValueError('path is not normalized: "%s"' % path)
+        if path[0] == "\\":
+            raise ValueError('path is absolute without a drive letter: "%s"' % path)
+        if os.path.isabs(path):
+            return path
+        return self._strategy.RlocationChecked(path)
+
+    def EnvVars(self):
+        """Returns environment variables for subprocesses.
+
+        The caller should set the returned key-value pairs in the environment of
+        subprocesses in case those subprocesses are also Bazel-built binaries that
+        need to use runfiles.
+
+        Returns:
+          {string: string}; a dict; keys are environment variable names, values are
+          the values for these environment variables
+        """
+        return self._strategy.EnvVars()
 
 
 class _ManifestBased(object):
-  """`Runfiles` strategy that parses a runfiles-manifest to look up runfiles."""
+    """`Runfiles` strategy that parses a runfiles-manifest to look up runfiles."""
 
-  def __init__(self, path):
-    if not path:
-      raise ValueError()
-    if not isinstance(path, str):
-      raise TypeError()
-    self._path = path
-    self._runfiles = _ManifestBased._LoadRunfiles(path)
+    def __init__(self, path):
+        if not path:
+            raise ValueError()
+        if not isinstance(path, str):
+            raise TypeError()
+        self._path = path
+        self._runfiles = _ManifestBased._LoadRunfiles(path)
 
-  def RlocationChecked(self, path):
-    return self._runfiles.get(path)
+    def RlocationChecked(self, path):
+        return self._runfiles.get(path)
 
-  @staticmethod
-  def _LoadRunfiles(path):
-    """Loads the runfiles manifest."""
-    result = {}
-    with open(path, "r") as f:
-      for line in f:
-        line = line.strip()
-        if line:
-          tokens = line.split(" ", 1)
-          if len(tokens) == 1:
-            result[line] = line
-          else:
-            result[tokens[0]] = tokens[1]
-    return result
+    @staticmethod
+    def _LoadRunfiles(path):
+        """Loads the runfiles manifest."""
+        result = {}
+        with open(path, "r") as f:
+            for line in f:
+                line = line.strip()
+                if line:
+                    tokens = line.split(" ", 1)
+                    if len(tokens) == 1:
+                        result[line] = line
+                    else:
+                        result[tokens[0]] = tokens[1]
+        return result
 
-  def _GetRunfilesDir(self):
-    if self._path.endswith("/MANIFEST") or self._path.endswith("\\MANIFEST"):
-      return self._path[:-len("/MANIFEST")]
-    elif self._path.endswith(".runfiles_manifest"):
-      return self._path[:-len("_manifest")]
-    else:
-      return ""
+    def _GetRunfilesDir(self):
+        if self._path.endswith("/MANIFEST") or self._path.endswith("\\MANIFEST"):
+            return self._path[: -len("/MANIFEST")]
+        elif self._path.endswith(".runfiles_manifest"):
+            return self._path[: -len("_manifest")]
+        else:
+            return ""
 
-  def EnvVars(self):
-    directory = self._GetRunfilesDir()
-    return {
-        "RUNFILES_MANIFEST_FILE": self._path,
-        "RUNFILES_DIR": directory,
-        # TODO(laszlocsomor): remove JAVA_RUNFILES once the Java launcher can
-        # pick up RUNFILES_DIR.
-        "JAVA_RUNFILES": directory,
-    }
+    def EnvVars(self):
+        directory = self._GetRunfilesDir()
+        return {
+            "RUNFILES_MANIFEST_FILE": self._path,
+            "RUNFILES_DIR": directory,
+            # TODO(laszlocsomor): remove JAVA_RUNFILES once the Java launcher can
+            # pick up RUNFILES_DIR.
+            "JAVA_RUNFILES": directory,
+        }
 
 
 class _DirectoryBased(object):
-  """`Runfiles` strategy that appends runfiles paths to the runfiles root."""
+    """`Runfiles` strategy that appends runfiles paths to the runfiles root."""
 
-  def __init__(self, path):
-    if not path:
-      raise ValueError()
-    if not isinstance(path, str):
-      raise TypeError()
-    self._runfiles_root = path
+    def __init__(self, path):
+        if not path:
+            raise ValueError()
+        if not isinstance(path, str):
+            raise TypeError()
+        self._runfiles_root = path
 
-  def RlocationChecked(self, path):
-    # Use posixpath instead of os.path, because Bazel only creates a runfiles
-    # tree on Unix platforms, so `Create()` will only create a directory-based
-    # runfiles strategy on those platforms.
-    return posixpath.join(self._runfiles_root, path)
+    def RlocationChecked(self, path):
+        # Use posixpath instead of os.path, because Bazel only creates a runfiles
+        # tree on Unix platforms, so `Create()` will only create a directory-based
+        # runfiles strategy on those platforms.
+        return posixpath.join(self._runfiles_root, path)
 
-  def EnvVars(self):
-    return {
-        "RUNFILES_DIR": self._runfiles_root,
-        # TODO(laszlocsomor): remove JAVA_RUNFILES once the Java launcher can
-        # pick up RUNFILES_DIR.
-        "JAVA_RUNFILES": self._runfiles_root,
-    }
+    def EnvVars(self):
+        return {
+            "RUNFILES_DIR": self._runfiles_root,
+            # TODO(laszlocsomor): remove JAVA_RUNFILES once the Java launcher can
+            # pick up RUNFILES_DIR.
+            "JAVA_RUNFILES": self._runfiles_root,
+        }
 
 
-def _PathsFrom(argv0, runfiles_mf, runfiles_dir, is_runfiles_manifest,
-               is_runfiles_directory):
-  """Discover runfiles manifest and runfiles directory paths.
+def _PathsFrom(
+    argv0, runfiles_mf, runfiles_dir, is_runfiles_manifest, is_runfiles_directory
+):
+    """Discover runfiles manifest and runfiles directory paths.
 
-  Args:
-    argv0: string; the value of sys.argv[0]
-    runfiles_mf: string; the value of the RUNFILES_MANIFEST_FILE environment
-      variable
-    runfiles_dir: string; the value of the RUNFILES_DIR environment variable
-    is_runfiles_manifest: lambda(string):bool; returns true if the argument is
-      the path of a runfiles manifest file
-    is_runfiles_directory: lambda(string):bool; returns true if the argument is
-      the path of a runfiles directory
+    Args:
+      argv0: string; the value of sys.argv[0]
+      runfiles_mf: string; the value of the RUNFILES_MANIFEST_FILE environment
+        variable
+      runfiles_dir: string; the value of the RUNFILES_DIR environment variable
+      is_runfiles_manifest: lambda(string):bool; returns true if the argument is
+        the path of a runfiles manifest file
+      is_runfiles_directory: lambda(string):bool; returns true if the argument is
+        the path of a runfiles directory
 
-  Returns:
-    (string, string) pair, first element is the path to the runfiles manifest,
-    second element is the path to the runfiles directory. If the first element
-    is non-empty, then is_runfiles_manifest returns true for it. Same goes for
-    the second element and is_runfiles_directory respectively. If both elements
-    are empty, then this function could not find a manifest or directory for
-    which is_runfiles_manifest or is_runfiles_directory returns true.
-  """
-  mf_alid = is_runfiles_manifest(runfiles_mf)
-  dir_valid = is_runfiles_directory(runfiles_dir)
-
-  if not mf_alid and not dir_valid:
-    runfiles_mf = argv0 + ".runfiles/MANIFEST"
-    runfiles_dir = argv0 + ".runfiles"
+    Returns:
+      (string, string) pair, first element is the path to the runfiles manifest,
+      second element is the path to the runfiles directory. If the first element
+      is non-empty, then is_runfiles_manifest returns true for it. Same goes for
+      the second element and is_runfiles_directory respectively. If both elements
+      are empty, then this function could not find a manifest or directory for
+      which is_runfiles_manifest or is_runfiles_directory returns true.
+    """
     mf_alid = is_runfiles_manifest(runfiles_mf)
     dir_valid = is_runfiles_directory(runfiles_dir)
+
+    if not mf_alid and not dir_valid:
+        runfiles_mf = argv0 + ".runfiles/MANIFEST"
+        runfiles_dir = argv0 + ".runfiles"
+        mf_alid = is_runfiles_manifest(runfiles_mf)
+        dir_valid = is_runfiles_directory(runfiles_dir)
+        if not mf_alid:
+            runfiles_mf = argv0 + ".runfiles_manifest"
+            mf_alid = is_runfiles_manifest(runfiles_mf)
+
+    if not mf_alid and not dir_valid:
+        return ("", "")
+
     if not mf_alid:
-      runfiles_mf = argv0 + ".runfiles_manifest"
-      mf_alid = is_runfiles_manifest(runfiles_mf)
+        runfiles_mf = runfiles_dir + "/MANIFEST"
+        mf_alid = is_runfiles_manifest(runfiles_mf)
+        if not mf_alid:
+            runfiles_mf = runfiles_dir + "_manifest"
+            mf_alid = is_runfiles_manifest(runfiles_mf)
 
-  if not mf_alid and not dir_valid:
-    return ("", "")
+    if not dir_valid:
+        runfiles_dir = runfiles_mf[:-9]  # "_manifest" or "/MANIFEST"
+        dir_valid = is_runfiles_directory(runfiles_dir)
 
-  if not mf_alid:
-    runfiles_mf = runfiles_dir + "/MANIFEST"
-    mf_alid = is_runfiles_manifest(runfiles_mf)
-    if not mf_alid:
-      runfiles_mf = runfiles_dir + "_manifest"
-      mf_alid = is_runfiles_manifest(runfiles_mf)
-
-  if not dir_valid:
-    runfiles_dir = runfiles_mf[:-9]  # "_manifest" or "/MANIFEST"
-    dir_valid = is_runfiles_directory(runfiles_dir)
-
-  return (runfiles_mf if mf_alid else "", runfiles_dir if dir_valid else "")
+    return (runfiles_mf if mf_alid else "", runfiles_dir if dir_valid else "")

diff --git a/tools/bazel_integration_test/test_runner.py b/tools/bazel_integration_test/test_runner.py
index 4e83d66..df7e528 100644
--- a/tools/bazel_integration_test/test_runner.py
+++ b/tools/bazel_integration_test/test_runner.py

@@ -1,16 +1,18 @@
-from pathlib import Path
 import json
 import os
 import platform
 import re
 import shutil
-from subprocess import Popen
 import sys
 import tempfile
+from pathlib import Path
+from subprocess import Popen
 
 from rules_python.python.runfiles import runfiles
+
 r = runfiles.Create()
 
+
 def modify_WORKSPACE(wksp, distro_path):
     """Update the WORKSPACE file in the example to point to our locally-built tar.gz
     This allows users to clone rules_python, cd into the example/dir, and run the example directly,
@@ -20,58 +22,64 @@
         wksp: filesystem absolute path of the bazel WORKSPACE file under test
         distro_path: runfiles path of the distro .tar.gz
     """
-    with open(wksp, 'r') as wksp_file:
+    with open(wksp, "r") as wksp_file:
         content = wksp_file.read()
     # Replace the url for rules_python with our locally built one
     content = re.sub(
         r'url = "https://github.com/bazelbuild/rules_python/[^"]+"',
         'url = "file://%s"' % r.Rlocation(distro_path),
-        content)
+        content,
+    )
     # comment out sha256 and strip_prefix if present
-    content = re.sub(r'sha256 = "', '#\1', content)
-    content = re.sub(r'strip_prefix = "', '#\1', content)
-    with open(wksp, 'w') as wksp_file:
+    content = re.sub(r'sha256 = "', "#\1", content)
+    content = re.sub(r'strip_prefix = "', "#\1", content)
+    with open(wksp, "w") as wksp_file:
         wksp_file.write(content)
 
+
 def main(conf_file):
     with open(conf_file) as j:
         config = json.load(j)
 
-    isWindows = platform.system() == 'Windows'
-    bazelBinary = r.Rlocation(os.path.join(config['bazelBinaryWorkspace'], 'bazel.exe' if isWindows else 'bazel'))
-    
-    workspacePath = config['workspaceRoot']
-    # Canonicalize bazel external/some_repo/foo
-    if workspacePath.startswith('external/'):
-        workspacePath = '..' + workspacePath[len('external'):]
+    isWindows = platform.system() == "Windows"
+    bazelBinary = r.Rlocation(
+        os.path.join(
+            config["bazelBinaryWorkspace"], "bazel.exe" if isWindows else "bazel"
+        )
+    )
 
-    with tempfile.TemporaryDirectory(dir = os.environ['TEST_TMPDIR']) as tmpdir:
+    workspacePath = config["workspaceRoot"]
+    # Canonicalize bazel external/some_repo/foo
+    if workspacePath.startswith("external/"):
+        workspacePath = ".." + workspacePath[len("external") :]
+
+    with tempfile.TemporaryDirectory(dir=os.environ["TEST_TMPDIR"]) as tmpdir:
         workdir = os.path.join(tmpdir, "wksp")
         print("copying workspace under test %s to %s" % (workspacePath, workdir))
         shutil.copytree(workspacePath, workdir)
 
-        modify_WORKSPACE(os.path.join(workdir, 'WORKSPACE'), config['distro'])
+        modify_WORKSPACE(os.path.join(workdir, "WORKSPACE"), config["distro"])
 
-        for command in config['bazelCommands']:
-            bazel_args = command.split(' ')
+        for command in config["bazelCommands"]:
+            bazel_args = command.split(" ")
             try:
-                doubleHyphenPos = bazel_args.index('--')
+                doubleHyphenPos = bazel_args.index("--")
                 print("patch that in ", doubleHyphenPos)
             except ValueError:
                 pass
 
-
-            # Bazel's wrapper script needs this or you get 
+            # Bazel's wrapper script needs this or you get
             # 2020/07/13 21:58:11 could not get the user's cache directory: $HOME is not defined
-            os.environ['HOME'] = str(Path.home())
+            os.environ["HOME"] = str(Path.home())
 
             bazel_args.insert(0, bazelBinary)
-            bazel_process = Popen(bazel_args, cwd = workdir)
+            bazel_process = Popen(bazel_args, cwd=workdir)
             bazel_process.wait()
             if bazel_process.returncode != 0:
                 # Test failure in Bazel is exit 3
                 # https://github.com/bazelbuild/bazel/blob/486206012a664ecb20bdb196a681efc9a9825049/src/main/java/com/google/devtools/build/lib/util/ExitCode.java#L44
                 sys.exit(3)
 
-if __name__ == '__main__':
-  main(sys.argv[1])
+
+if __name__ == "__main__":
+    main(sys.argv[1])

diff --git a/tools/wheelmaker.py b/tools/wheelmaker.py
index 9718e47..4b87a59 100644
--- a/tools/wheelmaker.py
+++ b/tools/wheelmaker.py

@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from pathlib import Path
 import argparse
 import base64
 import collections
@@ -21,6 +20,7 @@
 import re
 import sys
 import zipfile
+from pathlib import Path
 
 
 def commonpath(path1, path2):
@@ -38,8 +38,17 @@
 
 
 class WheelMaker(object):
-    def __init__(self, name, version, build_tag, python_tag, abi, platform,
-                 outfile=None, strip_path_prefixes=None):
+    def __init__(
+        self,
+        name,
+        version,
+        build_tag,
+        python_tag,
+        abi,
+        platform,
+        outfile=None,
+        strip_path_prefixes=None,
+    ):
         self._name = name
         self._version = version
         self._build_tag = build_tag
@@ -47,17 +56,23 @@
         self._abi = abi
         self._platform = platform
         self._outfile = outfile
-        self._strip_path_prefixes = strip_path_prefixes if strip_path_prefixes is not None else []
+        self._strip_path_prefixes = (
+            strip_path_prefixes if strip_path_prefixes is not None else []
+        )
 
-        self._distinfo_dir = (escape_filename_segment(self._name) + '-' +
-                              escape_filename_segment(self._version) +
-                              '.dist-info/')
+        self._distinfo_dir = (
+            escape_filename_segment(self._name)
+            + "-"
+            + escape_filename_segment(self._version)
+            + ".dist-info/"
+        )
         self._zipfile = None
         self._record = []
 
     def __enter__(self):
-        self._zipfile = zipfile.ZipFile(self.filename(), mode="w",
-                                        compression=zipfile.ZIP_DEFLATED)
+        self._zipfile = zipfile.ZipFile(
+            self.filename(), mode="w", compression=zipfile.ZIP_DEFLATED
+        )
         return self
 
     def __exit__(self, type, value, traceback):
@@ -69,7 +84,7 @@
         if self._build_tag:
             components.append(self._build_tag)
         components += [self._python_tag, self._abi, self._platform]
-        return '-'.join(components) + '.whl'
+        return "-".join(components) + ".whl"
 
     def filename(self) -> str:
         if self._outfile:
@@ -77,7 +92,7 @@
         return self.wheelname()
 
     def disttags(self):
-        return ['-'.join([self._python_tag, self._abi, self._platform])]
+        return ["-".join([self._python_tag, self._abi, self._platform])]
 
     def distinfo_path(self, basename):
         return self._distinfo_dir + basename
@@ -86,36 +101,37 @@
         # https://www.python.org/dev/peps/pep-0376/#record
         # "base64.urlsafe_b64encode(digest) with trailing = removed"
         digest = base64.urlsafe_b64encode(hash.digest())
-        digest = b'sha256=' + digest.rstrip(b'=')
+        digest = b"sha256=" + digest.rstrip(b"=")
         return digest
 
     def add_string(self, filename, contents):
         """Add given 'contents' as filename to the distribution."""
         if sys.version_info[0] > 2 and isinstance(contents, str):
-            contents = contents.encode('utf-8', 'surrogateescape')
+            contents = contents.encode("utf-8", "surrogateescape")
         self._zipfile.writestr(filename, contents)
         hash = hashlib.sha256()
         hash.update(contents)
-        self._add_to_record(filename, self._serialize_digest(hash),
-                            len(contents))
+        self._add_to_record(filename, self._serialize_digest(hash), len(contents))
 
     def add_file(self, package_filename, real_filename):
         """Add given file to the distribution."""
 
         def arcname_from(name):
             # Always use unix path separators.
-            normalized_arcname = name.replace(os.path.sep, '/')
+            normalized_arcname = name.replace(os.path.sep, "/")
             for prefix in self._strip_path_prefixes:
                 if normalized_arcname.startswith(prefix):
-                    return normalized_arcname[len(prefix):]
+                    return normalized_arcname[len(prefix) :]
 
             return normalized_arcname
 
         if os.path.isdir(real_filename):
             directory_contents = os.listdir(real_filename)
             for file_ in directory_contents:
-                self.add_file("{}/{}".format(package_filename, file_),
-                              "{}/{}".format(real_filename, file_))
+                self.add_file(
+                    "{}/{}".format(package_filename, file_),
+                    "{}/{}".format(real_filename, file_),
+                )
             return
 
         arcname = arcname_from(package_filename)
@@ -124,7 +140,7 @@
         # Find the hash and length
         hash = hashlib.sha256()
         size = 0
-        with open(real_filename, 'rb') as f:
+        with open(real_filename, "rb") as f:
             while True:
                 block = f.read(2 ** 20)
                 if not block:
@@ -140,13 +156,22 @@
 Wheel-Version: 1.0
 Generator: bazel-wheelmaker 1.0
 Root-Is-Purelib: {}
-""".format("true" if self._platform == "any" else "false")
+""".format(
+            "true" if self._platform == "any" else "false"
+        )
         for tag in self.disttags():
             wheel_contents += "Tag: %s\n" % tag
-        self.add_string(self.distinfo_path('WHEEL'), wheel_contents)
+        self.add_string(self.distinfo_path("WHEEL"), wheel_contents)
 
-    def add_metadata(self, extra_headers, description, classifiers, python_requires,
-                     requires, extra_requires):
+    def add_metadata(
+        self,
+        extra_headers,
+        description,
+        classifiers,
+        python_requires,
+        requires,
+        extra_requires,
+    ):
         """Write METADATA file to the distribution."""
         # https://www.python.org/dev/peps/pep-0566/
         # https://packaging.python.org/specifications/core-metadata/
@@ -167,29 +192,30 @@
             metadata.append("Provides-Extra: %s" % option)
             for requirement in option_requires:
                 metadata.append(
-                    "Requires-Dist: %s; extra == '%s'" % (requirement, option))
+                    "Requires-Dist: %s; extra == '%s'" % (requirement, option)
+                )
 
-        metadata = '\n'.join(metadata) + '\n\n'
+        metadata = "\n".join(metadata) + "\n\n"
         # setuptools seems to insert UNKNOWN as description when none is
         # provided.
         metadata += description if description else "UNKNOWN"
         metadata += "\n"
-        self.add_string(self.distinfo_path('METADATA'), metadata)
+        self.add_string(self.distinfo_path("METADATA"), metadata)
 
     def add_recordfile(self):
         """Write RECORD file to the distribution."""
-        record_path = self.distinfo_path('RECORD')
-        entries = self._record + [(record_path, b'', b'')]
+        record_path = self.distinfo_path("RECORD")
+        entries = self._record + [(record_path, b"", b"")]
         entries.sort()
-        contents = b''
+        contents = b""
         for filename, digest, size in entries:
             if sys.version_info[0] > 2 and isinstance(filename, str):
-                filename = filename.encode('utf-8', 'surrogateescape')
-            contents += b'%s,%s,%s\n' % (filename, digest, size)
+                filename = filename.encode("utf-8", "surrogateescape")
+            contents += b"%s,%s,%s\n" % (filename, digest, size)
         self.add_string(record_path, contents)
 
     def _add_to_record(self, filename, hash, size):
-        size = str(size).encode('ascii')
+        size = str(size).encode("ascii")
         self._record.append((filename, hash, size))
 
 
@@ -204,7 +230,9 @@
     return files
 
 
-def resolve_version_stamp(version: str, volatile_status_stamp: Path, stable_status_stamp: Path) -> str:
+def resolve_version_stamp(
+    version: str, volatile_status_stamp: Path, stable_status_stamp: Path
+) -> str:
     """Resolve workspace status stamps format strings found in the version string
 
     Args:
@@ -215,11 +243,14 @@
     Returns:
         str: A resolved version string
     """
-    lines = volatile_status_stamp.read_text().splitlines() + stable_status_stamp.read_text().splitlines()
+    lines = (
+        volatile_status_stamp.read_text().splitlines()
+        + stable_status_stamp.read_text().splitlines()
+    )
     for line in lines:
         if not line:
             continue
-        key, value = line.split(' ', maxsplit=1)
+        key, value = line.split(" ", maxsplit=1)
         stamp = "{" + key + "}"
         version = version.replace(stamp, value)
 
@@ -227,82 +258,114 @@
 
 
 def parse_args() -> argparse.Namespace:
-    parser = argparse.ArgumentParser(description='Builds a python wheel')
-    metadata_group = parser.add_argument_group(
-        "Wheel name, version and platform")
-    metadata_group.add_argument('--name', required=True,
-                                type=str,
-                                help="Name of the distribution")
-    metadata_group.add_argument('--version', required=True,
-                                type=str,
-                                help="Version of the distribution")
-    metadata_group.add_argument('--build_tag', type=str, default='',
-                                help="Optional build tag for the distribution")
-    metadata_group.add_argument('--python_tag', type=str, default='py3',
-                                help="Python version, e.g. 'py2' or 'py3'")
-    metadata_group.add_argument('--abi', type=str, default='none')
-    metadata_group.add_argument('--platform', type=str, default='any',
-                                help="Target platform. ")
+    parser = argparse.ArgumentParser(description="Builds a python wheel")
+    metadata_group = parser.add_argument_group("Wheel name, version and platform")
+    metadata_group.add_argument(
+        "--name", required=True, type=str, help="Name of the distribution"
+    )
+    metadata_group.add_argument(
+        "--version", required=True, type=str, help="Version of the distribution"
+    )
+    metadata_group.add_argument(
+        "--build_tag",
+        type=str,
+        default="",
+        help="Optional build tag for the distribution",
+    )
+    metadata_group.add_argument(
+        "--python_tag",
+        type=str,
+        default="py3",
+        help="Python version, e.g. 'py2' or 'py3'",
+    )
+    metadata_group.add_argument("--abi", type=str, default="none")
+    metadata_group.add_argument(
+        "--platform", type=str, default="any", help="Target platform. "
+    )
 
     output_group = parser.add_argument_group("Output file location")
-    output_group.add_argument('--out', type=str, default=None,
-                              help="Override name of ouptut file")
-    output_group.add_argument('--name_file', type=Path,
-                              help="A file where the canonical name of the "
-                                   "wheel will be written")
+    output_group.add_argument(
+        "--out", type=str, default=None, help="Override name of ouptut file"
+    )
+    output_group.add_argument(
+        "--name_file",
+        type=Path,
+        help="A file where the canonical name of the " "wheel will be written",
+    )
 
-    output_group.add_argument('--strip_path_prefix',
-                              type=str,
-                              action="append",
-                              default=[],
-                              help="Path prefix to be stripped from input package files' path. "
-                                   "Can be supplied multiple times. "
-                                   "Evaluated in order."
-                              )
+    output_group.add_argument(
+        "--strip_path_prefix",
+        type=str,
+        action="append",
+        default=[],
+        help="Path prefix to be stripped from input package files' path. "
+        "Can be supplied multiple times. "
+        "Evaluated in order.",
+    )
 
     wheel_group = parser.add_argument_group("Wheel metadata")
     wheel_group.add_argument(
-        '--header', action='append',
+        "--header",
+        action="append",
         help="Additional headers to be embedded in the package metadata. "
-             "Can be supplied multiple times.")
-    wheel_group.add_argument('--classifier', action='append',
-                             help="Classifiers to embed in package metadata. "
-                                  "Can be supplied multiple times")
-    wheel_group.add_argument('--python_requires',
-                             help="Version of python that the wheel will work with")
-    wheel_group.add_argument('--description_file',
-                             help="Path to the file with package description")
-    wheel_group.add_argument('--entry_points_file',
-                             help="Path to a correctly-formatted entry_points.txt file")
+        "Can be supplied multiple times.",
+    )
+    wheel_group.add_argument(
+        "--classifier",
+        action="append",
+        help="Classifiers to embed in package metadata. "
+        "Can be supplied multiple times",
+    )
+    wheel_group.add_argument(
+        "--python_requires", help="Version of python that the wheel will work with"
+    )
+    wheel_group.add_argument(
+        "--description_file", help="Path to the file with package description"
+    )
+    wheel_group.add_argument(
+        "--entry_points_file",
+        help="Path to a correctly-formatted entry_points.txt file",
+    )
 
     contents_group = parser.add_argument_group("Wheel contents")
     contents_group.add_argument(
-        '--input_file', action='append',
+        "--input_file",
+        action="append",
         help="'package_path;real_path' pairs listing "
-             "files to be included in the wheel. "
-             "Can be supplied multiple times.")
+        "files to be included in the wheel. "
+        "Can be supplied multiple times.",
+    )
     contents_group.add_argument(
-        '--input_file_list', action='append',
-        help='A file that has all the input files defined as a list to avoid the long command'
+        "--input_file_list",
+        action="append",
+        help="A file that has all the input files defined as a list to avoid the long command",
     )
 
     requirements_group = parser.add_argument_group("Package requirements")
     requirements_group.add_argument(
-        '--requires', type=str, action='append',
-        help="List of package requirements. Can be supplied multiple times.")
+        "--requires",
+        type=str,
+        action="append",
+        help="List of package requirements. Can be supplied multiple times.",
+    )
     requirements_group.add_argument(
-        '--extra_requires', type=str, action='append',
+        "--extra_requires",
+        type=str,
+        action="append",
         help="List of optional requirements in a 'requirement;option name'. "
-             "Can be supplied multiple times.")
+        "Can be supplied multiple times.",
+    )
 
     build_group = parser.add_argument_group("Building requirements")
     build_group.add_argument(
-        '--volatile_status_file', type=Path,
-        help="Pass in the stamp info file for stamping"
+        "--volatile_status_file",
+        type=Path,
+        help="Pass in the stamp info file for stamping",
     )
     build_group.add_argument(
-        '--stable_status_file', type=Path,
-        help="Pass in the stamp info file for stamping"
+        "--stable_status_file",
+        type=Path,
+        help="Pass in the stamp info file for stamping",
     )
 
     return parser.parse_args(sys.argv[1:])
@@ -312,7 +375,7 @@
     arguments = parse_args()
 
     if arguments.input_file:
-        input_files = [i.split(';') for i in arguments.input_file]
+        input_files = [i.split(";") for i in arguments.input_file]
     else:
         input_files = []
 
@@ -321,7 +384,7 @@
             with open(input_file) as _file:
                 input_file_list = _file.read().splitlines()
             for _input_file in input_file_list:
-                input_files.append(_input_file.split(';'))
+                input_files.append(_input_file.split(";"))
 
     all_files = get_files_to_package(input_files)
     # Sort the files for reproducible order in the archive.
@@ -330,21 +393,24 @@
     strip_prefixes = [p for p in arguments.strip_path_prefix]
 
     if arguments.volatile_status_file and arguments.stable_status_file:
-        version = resolve_version_stamp(arguments.version,
-                                        arguments.volatile_status_file,
-                                        arguments.stable_status_file)
+        version = resolve_version_stamp(
+            arguments.version,
+            arguments.volatile_status_file,
+            arguments.stable_status_file,
+        )
     else:
         version = arguments.version
 
-    with WheelMaker(name=arguments.name,
-                    version=version,
-                    build_tag=arguments.build_tag,
-                    python_tag=arguments.python_tag,
-                    abi=arguments.abi,
-                    platform=arguments.platform,
-                    outfile=arguments.out,
-                    strip_path_prefixes=strip_prefixes
-                    ) as maker:
+    with WheelMaker(
+        name=arguments.name,
+        version=version,
+        build_tag=arguments.build_tag,
+        python_tag=arguments.python_tag,
+        abi=arguments.abi,
+        platform=arguments.platform,
+        outfile=arguments.out,
+        strip_path_prefixes=strip_prefixes,
+    ) as maker:
         for package_filename, real_filename in all_files:
             maker.add_file(package_filename, real_filename)
         maker.add_wheelfile()
@@ -352,34 +418,37 @@
         description = None
         if arguments.description_file:
             if sys.version_info[0] == 2:
-                with open(arguments.description_file,
-                          'rt') as description_file:
+                with open(arguments.description_file, "rt") as description_file:
                     description = description_file.read()
             else:
-                with open(arguments.description_file, 'rt',
-                          encoding='utf-8') as description_file:
+                with open(
+                    arguments.description_file, "rt", encoding="utf-8"
+                ) as description_file:
                     description = description_file.read()
 
         extra_requires = collections.defaultdict(list)
         if arguments.extra_requires:
             for extra in arguments.extra_requires:
-                req, option = extra.rsplit(';', 1)
+                req, option = extra.rsplit(";", 1)
                 extra_requires[option].append(req)
         classifiers = arguments.classifier or []
         python_requires = arguments.python_requires or ""
         requires = arguments.requires or []
         extra_headers = arguments.header or []
 
-        maker.add_metadata(extra_headers=extra_headers,
-                           description=description,
-                           classifiers=classifiers,
-                           python_requires=python_requires,
-                           requires=requires,
-                           extra_requires=extra_requires)
+        maker.add_metadata(
+            extra_headers=extra_headers,
+            description=description,
+            classifiers=classifiers,
+            python_requires=python_requires,
+            requires=requires,
+            extra_requires=extra_requires,
+        )
 
         if arguments.entry_points_file:
-            maker.add_file(maker.distinfo_path(
-                "entry_points.txt"), arguments.entry_points_file)
+            maker.add_file(
+                maker.distinfo_path("entry_points.txt"), arguments.entry_points_file
+            )
 
         maker.add_recordfile()
 
@@ -390,5 +459,5 @@
         arguments.name_file.write_text(maker.wheelname())
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main()