def METHOD_NAME(self):
    def f():
        "hello"
        return 42
    self.assertEqual(f.__doc__, "hello")
    f.__doc__ = "world"
    self.assertEqual(f.__doc__, "world")
    # Setting to a non-string is odd but allowed:
    f.__doc__ = 42
    self.assertEqual(f.__doc__, 42)
    # Attemping to delete __doc__ instead sets it to None:
    del f.__doc__
    self.assertEqual(f.__doc__, None)