def lookup(self, portOnServer, portOnClient):
        """
        Lookup user information about the specified address pair.
        """
        self.queries.append((defer.Deferred(), portOnServer, portOnClient))
        if len(self.queries) > 1:
            return self.queries[-1][0]

        self.sendLine('%d, %d' % (portOnServer, portOnClient))
        return self.queries[-1][0]

        Lookup user information about the specified address pair.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/ident.py