Take advantage of caching and the lru_cache decorator to relieve your Python functions from repetitive heavy lifting.

Python lets you set default values for function arguments, which is super convenient. But when those default values are mutable (like lists or dictionaries), you're walking into a sneaky bug trap.

Python Functions: Python Functions, Function Argument, Python Recursion Anonymous Function, Global, Local and Nonlocal, Python Global Keyword, Python Modules, Python Package.