def delete_key(self, network_id):
        try:
            tunnel_key = self[network_id]
            self.send_event(EventTunnelKeyDel(network_id, tunnel_key))
            del self[network_id]
        except __HOLE__:
            raise ryu_exc.NetworkNotFound(network_id=network_id)
dataset/ETHPy150Open osrg/ryu/ryu/controller/tunnels.py/TunnelKeys.delete_key