Name of a Python function in a stack trace

Question

In both Python2 and Python3, in the stack trace the __name__ of a function is not used, the original name (the one that is specified after def) is

Answer 1

Tried to explore the CPython implementation, definitely not an expert. As pointed out in the comments, when the stack entry of f is printed, the attribute f.__code__.co_name is used. Also, f.__name__ is initially set to f.__code__.co_name, but when you modify the former, the latter is not modified accordingly.

Therefore, I tried to modify that directly, but it is not possible:

>>> f.__code__.co_name = 'g'
Traceback (most recent call last):
  File "", line 1, in 
TypeError: readonly attribute
>>>

Why are there two ways to say a function's name? Well, according to the documentation, __name__ is defined for "class, function, method, descriptor, or generator instance", so in the case of functions it maps to that attribute, for other objects it will map to something else.