def assertNotUnequal(self, first, second, msg=None):
        """
        Tests that C{first} != C{second} is false.  This method tests the
        __ne__ method, as opposed to L{assertEqual} (C{first} == C{second}),
        which tests the __eq__ method.

        Note: this should really be part of trial
        """
        if first != second:
            if msg is None:
                msg = '';
            if len(msg) > 0:
                msg += '\n'
            raise self.failureException(
                '%snot not unequal (__ne__ not implemented correctly):'
                '\na = %s\nb = %s\n'
                % (msg, pformat(first), pformat(second)))
        return first

        Tests that C{first} != C{second} is false.  This method tests the
        __ne__ method, as opposed to L{assertEqual} (C{first} == C{second}),
        which tests the __eq__ method.

        Note: this should really be part of trial
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_paths.py