docs: def _process_method_frame(self, channel, payload):
          """
          Process Method frames
  
          """
          method_sig = unpack('>HH', payload[:4])
          args = AMQPReader(payload[4:])
  
          if method_sig in _CONTENT_METHODS:
              #
              # Save what we've got so far and wait for the content-header
              #
              self.partial_messages[channel] = _PartialMessage(method_sig, args)
              self.expected_types[channel] = 2
          else:
              self.queue.put((channel, method_sig, args, None))