class_docstr: Example one person world that uses only user input.
class_docstr_tok: ["Example","one","person","world","that","uses","only","user","input","."]
code: def parley(self):
      a = self.agent.act()
      if a is not None:
          if "[DONE]" in a["text"]:
              self.episodeDone = True
          else:
              a["id"] = "World"
              self.agent.observe(a)
  
imports: from parlai.core.worlds import World
  from parlai.chat_service.services.messenger.worlds import OnboardWorld
label_desc: Use image node_id 4 for calling the MessengerEchoTaskWorld obj's underlying member method code with example usage: obj.parley() without return types