"It isn’t other best practices story about how to develop better in Python."

Funnily enough it turns out to be another best practices story.

That being said, the ´issue´ your friend encountered has nothing to do with Python itself.

I´ve seen that type of issue pop-up many times when (part of) development is outsourced to a third party without specifying to / agreeing with them the quality criteria the code must meet and how such needs to be evidenced.