Shadowing a class attribute via assignment

Question

Accepted Answer

When you do `c1.debug = True`, Python creates an instance attribute on `c1` that shadows the class attribute for that object only. Later setting `Config.debug = False` changes the class attribute, but `c1` already has its own instance-level `debug`, so looking it up on `c1` still finds `True`. `c2` has no instance attribute, so it reads from the class and gets `False`. This shadowing behavior is one of the most common OOP gotchas in Python.