def test_uncleanServerSocketLocking(self):
        """
        If passed C{True} for the C{wantPID} parameter, a server can be started
        listening with L{IReactorUNIX.listenUNIX} when passed the name of a
        file on which a previous server which has not exited cleanly has been
        listening using the C{wantPID} option.
        """
        def ranStupidChild(ign):
            # If this next call succeeds, our lock handling is correct.
            p = reactor.listenUNIX(self.filename, MyServerFactory(), wantPID=True)
            return p.stopListening()
        return self._uncleanSocketTest(ranStupidChild)

        If passed C{True} for the C{wantPID} parameter, a server can be started
        listening with L{IReactorUNIX.listenUNIX} when passed the name of a
        file on which a previous server which has not exited cleanly has been
        listening using the C{wantPID} option.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_unix.py