Collections_extended is a pure Python module with no dependencies providing:

* a bag class, also known as multiset, * a setlist class, which is a unique list or ordered set, * a bijection class, RangeMap which is a mapping from ranges to values, * a IndexedDict class, which is an ordered mapping whose elements can be accessed using index, in addition to key.

There are also frozen (hashable) varieties of bags and setlists.

This package installs the library for Python 3.