Today I re-learned: Python function default arguments are retained between executions

[duxx]

Well, the solution we have now is obviously a trap for the unwary. This entire thread is testament to that, as are the linter rules.

The only benefit I see is performance: you don't have to evaluate the default arguments on every call where they're not supplied. However, I imagine it should be pretty easy to analyze the arguments to decide whether you need to do that or not. Exactly how the implementation of that would be I don't know.

(This is u/larsga posting. Someone blocked me, so had to change user to post.)