code: def on_message(self, msg):
          
          if self not in clients:
              return
  
          try:
              payload = json_decode(msg)
          except ValueError:
              # unable to decode so we cannot handle the message
              return
  
          if 'close' in payload:
              self.close()
              return
  
          for verb, args in payload.items():
              self.group.action(verb, args)
docs: Accept a message that was published, process and forward
  
          Parameters
          ----------
          msg : str
              The message sent over the line
  
          Notes
          -----
          This method only handles messages where `message_type` is "message".