def test_multipleDelayedCalls(self):
        """
        If there are several delayed calls, C{doIteration} is called with a
        timeout which is the difference between the current time and the
        time at which the earlier of the two calls is to run.
        """
        reactor = TimeoutReportReactor()
        reactor.callLater(50, lambda: None)
        reactor.callLater(10, lambda: None)
        reactor.callLater(100, lambda: None)
        timeout = self._checkIterationTimeout(reactor)
        self.assertEqual(timeout, 10)

        If there are several delayed calls, C{doIteration} is called with a
        timeout which is the difference between the current time and the
        time at which the earlier of the two calls is to run.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_posixbase.py