def test_deque(self):
        """
        Test references search through a deque object.
        """
        o = object()
        D = deque()
        D.append(None)
        D.append(o)

        self.assertIn("[1]", reflect.objgrep(D, o, reflect.isSame))

        Test references search through a deque object.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_reflect.py