def setUp(self):
        """
        Create a new XML-RPC server with C{allowNone} set to C{True}.
        """
        kwargs = {self.flagName: True}
        self.p = reactor.listenTCP(
            0, server.Site(Test(**kwargs)), interface="127.0.0.1")
        self.addCleanup(self.p.stopListening)
        self.port = self.p.getHost().port
        self.proxy = xmlrpc.Proxy(
            networkString("http://127.0.0.1:%d/" % (self.port,)), **kwargs)

        Create a new XML-RPC server with C{allowNone} set to C{True}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_xmlrpc.py