docs: def rpc_reply(channel, original_headers, message, properties=None):
  	"""
  	Reply to a RPC request. This function will use the default exchange, to directly contact the reply_to queue.
  
  	Parameters
  	----------
  	channel: object
  		Properly initialized AMQP channel to use.
  	original_headers: dict
  		The headers of the originating message that caused this reply.
  	message: string
  		Message to reply with
  	properties: dict
  		Properties to set on message. This parameter is optional, but if set, at least the following options must be set:
  			content_type: string - what content_type to specify, default is 'text/plain'.
  			delivery_mode: int - what delivery_mode to use. By default message are not persistent, but this can be
  				set by specifying PERSISTENT_MESSAGE .
  	"""
  	if not properties:
  		properties = {}
  	properties['correlation_id'] = original_headers.correlation_id
  
  	publish_message(channel, '', original_headers.reply_to, message, properties)