def test_makeCopy(self):
        """
        L{util.padTo} doesn't modify the input list but makes a copy.
        """
        items = []
        util.padTo(4, items)
        self.assertEqual([], items)

        L{util.padTo} doesn't modify the input list but makes a copy.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/python/test/test_util.py