'Check if we know who the coordinator is and have an active connection
Side-effect: reset coordinator_id to None if connection failed
Returns:
bool: True if the coordinator is unknown'

def coordinator_unknown(self):

    if (self.coordinator_id is None):
        return True
    if self._client.is_disconnected(self.coordinator_id):
        self.coordinator_dead('Node    Disconnected')
        return True
    return False
