def test_notExists(self):
        """
        Nonexistent PID file is not an error.
        """
        self.patch(os.path, "exists", lambda _: False)
        checkPID("non-existent PID file")

        Nonexistent PID file is not an error.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_twistd.py