python - Setting attributes on __func__ -

in documentation on instance methods states that:

methods support accessing (but not setting) arbitrary function attributes on underlying function object.

but can't seem able verify restriction. tried setting both arbitrary value , 1 of "special attributes" of functions:

class cls:     def foo(self):         f = self.foo.__func__         f.a = "some value"  # arbitrary value         f.__doc__ = "documentation"         print(f.a, f.__doc__) 

when executed, no errors produced , output expected:

cls().foo() # prints out f.a, f.__doc__ 

what i'm misunderstanding documentation?

you misunderstanding being said. says can access not set attributes of underlying function object from method!

>>> class foo: ...     def foo(self): ...         self.foo.__func__.a = 1 ...         print(self.foo.a) ...         self.foo.a = 2 ...  >>> foo().foo() 1 traceback (most recent call last):   file "<stdin>", line 1, in <module>   file "<stdin>", line 5, in foo attributeerror: 'method' object has no attribute 'a' 

note how foo.a updated when set on __func__ value, cannot set directly using self.foo.a = value.

so function object can modified please, method wrapper provides read-only access attributes on underlying function.