docs: def tx_id(properties):
          """
          Gets the tx_id for a message from a rabbit queue, using the
          message properties. Will raise KeyError if tx_id is missing from message
          headers.
  
          : param properties: Message properties
  
          : returns: tx_id of survey response
          : rtype: str
          """
          tx_id = properties.headers['tx_id']
          logger.info("Retrieved tx_id from message properties: tx_id={}".format(tx_id))
          return tx_id