def test_depthLimit(self):
        """
        Test the depth of references search.
        """
        a = []
        b = [a]
        c = [a, b]
        d = [a, c]

        self.assertEqual(['[0]'], reflect.objgrep(d, a, reflect.isSame, maxDepth=1))
        self.assertEqual(['[0]', '[1][0]'], reflect.objgrep(d, a, reflect.isSame, maxDepth=2))
        self.assertEqual(['[0]', '[1][0]', '[1][1][0]'], reflect.objgrep(d, a, reflect.isSame, maxDepth=3))

        Test the depth of references search.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_reflect.py