class_docstr: Simple interactive world involving just two agents talking.
  
  In more sophisticated worlds the environment could supply information, e.g. in
  tasks/convai2 both agents are given personas, so a world class should be written
  especially for those cases for given tasks.
code: def add_cmdline_args(
      cls, parser: ParlaiParser, partial_opt: Optional[Opt] = None
  ) -> ParlaiParser:
      # no default args
      return parser
  
file_path: ParlAI/parlai/tasks/interactive/worlds.py
imports: from copy import deepcopy
  from typing import Optional
  from parlai.core.opt import Opt
  from parlai.core.params import ParlaiParser
  from parlai.core.worlds import DialogPartnerWorld, validate
  from parlai.core.message import Message
label_desc: Use image node_id 1 for calling the InteractiveWorld obj's underlying member method code with example usage: obj.add_cmdline_args(cls, parser, partial_opt) and returns: parser