def setUp(self):
        """
        Set up a timer service to test.
        """
        self.timer = TimerService(2, self.call)
        self.clock = self.timer.clock = task.Clock()
        self.deferred = Deferred()

        Set up a timer service to test.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/application/test/test_internet.py