040000 tree 0cfae72811cde3b2c3e3150eafb4ababbbfa6f58	check
040000 tree c9308b20230c726ddcbd4c1026711954576099c2	examples
040000 tree 18afc0414e48132dac62dc972668165efbbc68b5	fixedbugs
040000 tree 4a320f60704c2a39b4ca1543527d27a77982a1eb	spec