def test_noOpByDefault(self):
        """
        On Python 3 or on Py2 when C{TWISTED_NEWSTYLE} is not set,
        L{_oldStyle._oldStyle} is a no-op.
        """
        updatedClass = _oldstyle._oldStyle(SomeOldStyleClass)
        self.assertEqual(type(updatedClass), type(SomeOldStyleClass))
        self.assertIs(updatedClass, SomeOldStyleClass)

        On Python 3 or on Py2 when C{TWISTED_NEWSTYLE} is not set,
        L{_oldStyle._oldStyle} is a no-op.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_nooldstyle.py