Mutmut: A Python mutation testing system (2016)

Interesting to see the genesis story for mutmut. It has come a long way since its inception: https://pypi.org/project/mutmut/

Mutation testing is a new concept for me, and even though one has to manage the performance aspects of it, it seems like a good idea to at least apply to selected functions in one's codebase, in order to find bugs.