def test_inheritedErrorAddition(self):
        """
        Verify that new errors specified in a subclass of an existing command
        are honored even if the superclass defines some errors.
        """
        return self.errorCheck(
            OtherInheritedError, AddedCommandProtocol, AddErrorsCommand, other=True)

        Verify that new errors specified in a subclass of an existing command
        are honored even if the superclass defines some errors.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_amp.py