040000 tree d62ab9d19706a39099888b8d61856df0874c7819	item-collection
040000 tree 32c1b0414e7646180b9cf4858615bbd0d68b65dc	partitioning
040000 tree 3d237430c68f3922d72bb03ce0b0562e0c7be3cc	polymorphization