def test_nonNumeric(self):
        """
        Non-numeric content in a PID file causes a system exit.
        """
        pidfile = self.mktemp()
        with open(pidfile, "w") as f:
            f.write("non-numeric")
        e = self.assertRaises(SystemExit, checkPID, pidfile)
        self.assertIn("non-numeric value", e.code)

        Non-numeric content in a PID file causes a system exit.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_twistd.py