Your test suite tells you about the quality of your code under test.
Mutation testing is a way to tell you about the quality your test suite.
Anders Hovmöller wrote mutmut (https://mutmut.readthedocs.io/) for mutation testing in Python, and can be used with pytest, unittest, and others.
In this episode, Anders explains mutation testing, how mutation testing with mutmut works, and good workflows.
Special Guest: Anders Hovmöller.