def opt_localforward(self, f):
        """
        Forward local port to remote address (lport:host:port)
        """
        localPort, remoteHost, remotePort = f.split(':')  # Doesn't do v6 yet
        localPort = int(localPort)
        remotePort = int(remotePort)
        self.localForwards.append((localPort, (remoteHost, remotePort)))

        Forward local port to remote address (lport:host:port)
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/scripts/conch.py