docs: def reactToAMQPMessage(message, send_back):
      """
      React to given (AMQP) message. `message` is usually expected to be
      :py:func:`collections.namedtuple` structure filled with all necessary data.
  
      Args:
          message (\*Request class): only :class:`.ConversionRequest` class is
                                     supported right now
  
          send_back (fn reference): Reference to function for responding. This is
                    useful for progress monitoring for example. Function takes
                    one parameter, which may be response structure/namedtuple, or
                    string or whatever would be normally returned.
  
      Returns:
          ConversionResponse: response filled with data about conversion and\
                              converted file.
  
      Raises:
          ValueError: if bad type of `message` structure is given.
      """
      if _instanceof(message, ConversionRequest):
          return convert(
              message.input_format,
              message.output_format,
              message.b64_data
          )
  
      raise ValueError(
          "Unknown type of request: '" + str(type(message)) + "'!"
      )