code: def ack(self, delivery_tag):
      self._get_channel()
      return self._channel.basic_ack(delivery_tag=delivery_tag)
  
file_path: FATE/python/fate/arch/federation/backends/rabbitmq/_mq_channel.py
imports: import json
  import logging
  import pika
  from fate.arch.federation.message_queue import nretry
label_desc: Use image node_id 6 for calling the MQChannel obj's underlying member method code with example usage: obj.ack(delivery_tag) and returns: self