def test_captureSIGINT(self):
        """
        ReactorBase's SIGINT handler saves the value of SIGINT to the
        _exitSignal attribute.
        """
        reactor = TestSpySignalCapturingReactor()
        reactor.sigInt(signal.SIGINT, None)
        self.assertEquals(signal.SIGINT, reactor._exitSignal)

        ReactorBase's SIGINT handler saves the value of SIGINT to the
        _exitSignal attribute.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_base.py