def test_cancelTimeout(self):
        """
        Setting the timeout to L{None} cancel any timeout operations.
        """
        self.proto.timeOut = 5
        self.proto.makeConnection(StringTransport())

        self.proto.setTimeout(None)
        self.assertIsNone(self.proto.timeOut)

        self.clock.pump([0, 5, 5, 5])
        self.assertFalse(self.proto.timedOut)

        Setting the timeout to L{None} cancel any timeout operations.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_policies.py