class_docstr: Reverses all the turns in a conversation.
  
  Labels remain in the original ordering, but the order of text (prompts) is mixed up.
  Thus "one half" of the conversation is reordered.
class_docstr_tok: ["Reverses","all","the","turns","in","a","conversation",".","Labels","remain","in","the","original","ordering",",","but","the","order","of","text","(","prompts",")","is","mixed","up",".","Thus","``","one","half","''","of","the","conversation","is","reordered","."]
code: def add_cmdline_args(
      cls, parser: ParlaiParser, partial_opt: Optional[Opt] = None
  ) -> ParlaiParser:
      parser.add_argument(
          "--preserve-context",
          default=True,
          type="bool",
          help="If extra context is provided, keep it prepended to the first turn",
      )
  
file_path: ParlAI/parlai/mutators/episode_reverse.py
imports: import random
  from typing import List, Optional
  from parlai.core.opt import Opt
  from parlai.core.message import Message
  from parlai.core.mutators import register_mutator, EpisodeMutator
  from parlai.core.params import ParlaiParser
label_desc: Use image node_id 1 for calling the EpisodeReverseMutator obj's underlying member method code with example usage: obj.add_cmdline_args(cls, parser, partial_opt) without return types