Question

How to check if a function is a method of some object?

For example:

def check_method(f):
    ...

check_method(lambda x: x + 1)           # >>> False
check_method(SomeClass().some_method)  # >>> True

There are some special attributes in methods in my ‘helloworld’ example (e.g. ‘im_self’, ‘__self__’ etc). Can I rely on them or there is some nicer way?

Answer 1

Use inspect.ismethod().

The documentation states:

Return true if the object is a bound method written in Python.

This means that it will work as you intend for classes that you define in Python. However, for methods of built-in classes like list or classes implemented in extension modules it will return False.