def test_circularTuple(self):
        """
        L{aot.jellyToAOT} can persist circular references through tuples.
        """
        l = []
        t = (l, 4321)
        l.append(t)
        j1 = aot.jellyToAOT(l)
        oj = aot.unjellyFromAOT(j1)
        self.assertIsInstance(oj[0], tuple)
        self.assertIs(oj[0][0], oj)
        self.assertEqual(oj[0][1], 4321)

        L{aot.jellyToAOT} can persist circular references through tuples.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_persisted.py