def test_isRunningDoesExist(self):
        """
        L{PIDFile.isRunning} returns true for a process that does exist.
        """
        pidFile = PIDFile(DummyFilePath())
        pidFile._write(1337)

        def kill(pid, signal):
            return  # Don't actually kill anything

        self.patch(_pidfile, "kill", kill)

        self.assertTrue(pidFile.isRunning())

        L{PIDFile.isRunning} returns true for a process that does exist.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/application/runner/test/test_pidfile.py