040000 tree 029628d186ea8355a11db4a74ada5442ba5a0c3c	check
040000 tree 1a74986db257983d88a44e31c4ad4cf02ec7761a	examples
040000 tree 6cbc1ff12370d2db4bfcaa665977e8c02334ca08	fixedbugs
040000 tree d87f6dffc05837f5ebb007491668baefbf58b481	spec