def setUp(self):
        """
        Create two L{DelayedCall} instanced scheduled to run at different
        times.
        """
        self.zero = self._getDelayedCallAt(0)
        self.one = self._getDelayedCallAt(1)

        Create two L{DelayedCall} instanced scheduled to run at different
        times.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_base.py