040000 tree ddc0d2d357cd5c5d60911ab824922c5fe10a5b0e	collection
040000 tree 1e156f5449ada98fd67365ea27af284e7ebe3bda	iterable
040000 tree 62358c751f7ddfb4cb72dc60bdb5606f86340c5b	iterator
040000 tree 79fad17248cc76d61ecb5b3d66e6972e47edc580	list
040000 tree 7788b3d3a4916d0e8bcefb472576ccefdcfd4904	map
040000 tree d40835b5d40f01db5535b01a4bc7ad26305fda4e	optional
040000 tree 6e2006723231804c9b8876e8f46ade4d4360aece	references