all Python 3inspectfunction

inspect.ismethoddescriptor()

descriptors

Checks that an object is a method descriptor: it has __get__ but neither __set__ nor __delete__ (for example int.__add__, list.append).

Syntax

inspect.ismethoddescriptor(object) -> bool

Functions and classes are excluded even though a function has __get__: ismethoddescriptor returns False for them because isfunction and isclass 'promise more'. The classmethod and staticmethod objects taken from a class __dict__, however, are method descriptors. The typical place you meet one is list.append: it is neither a builtin nor a function but exactly a method descriptor.

Examples

import inspect
class A:
    def m(self): pass
    @classmethod
    def cm(cls): pass
print(inspect.ismethoddescriptor(list.append))  # → True
print(inspect.ismethoddescriptor(A.__dict__['m']))  # → False — это функция
print(inspect.ismethoddescriptor(A.__dict__['cm']))  # → True

See also

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