code: def process_message(self, ch, method, properties, body):
          
          self.work_request = pickle.loads(body)
          ch.basic_ack(delivery_tag=method.delivery_tag)
          self.process_work_request()
docs: Callback method that is fired for every message that comes in while we are in process_messages_loop.
          :param ch: channel message was sent on
          :param method: pika.Basic.Deliver
          :param properties: pika.BasicProperties
          :param body: str: payload of the message (picked WorkRequest)