def is_known_dead_instance(self, instance_id):
        if self._live_instances is None:
            return False
        return instance_id not in self._live_instances
If the node identified by given ID is dead, return ``True``. If it's
dataset/ETHPy150Open ClusterHQ/flocker/flocker/node/agents/blockdevice.py/RawState.is_known_dead_instance