class_docstr: Passthrough world to spawn task worlds of only one type.
  
  Demos of more advanced overworld functionality exist in the overworld demo
code: def episode_done(self):
      return self.episodeDone
  
file_path: ParlAI/parlai/chat_service/services/messenger/worlds.py
imports: from parlai.core.worlds import World
label_desc: Use image node_id 2 for calling the SimpleMessengerOverworld obj's underlying member method code with example usage: obj.episode_done() and returns: self