python-intbitset 2.3.0-2 (amd64 binary) in ubuntu bionic

 The ``intbitset`` library provides a set implementation to store sorted
 unsigned integers either 32-bits integers (between ``0`` and
 ``2**31 - 1`` or ``intbitset.__maxelem__``) or an infinite range
 with fast set operations implemented via bit vectors in a *Python C
 extension* for speed and reduced memory usage.