040000 tree 0cfae72811cde3b2c3e3150eafb4ababbbfa6f58	check
040000 tree c9308b20230c726ddcbd4c1026711954576099c2	examples
040000 tree 18afc0414e48132dac62dc972668165efbbc68b5	fixedbugs
040000 tree 350b70f3693fa488bf35ff2850425bbb6bb4f603	spec