class_docstr: Chunks '__retrieved-docs__' into smaller docs (max 100 words each).
code: def message_mutation(self, message: Message) -> Message:
      chunk_sz = self.opt.get("woi_doc_chunk_size", 500)
      return chunk_docs_in_message(message, chunk_sz)
  
imports: import torch
  from parlai.core.mutators import register_mutator, MessageMutator, ManyEpisodeMutator
  from typing import Optional
  from parlai.core.opt import Opt
  from parlai.core.message import Message
  from parlai.core.params import ParlaiParser
  import parlai.tasks.wizard_of_internet.constants
  from parlai.tasks.wizard_of_wikipedia.mutators import AddLabel, AddLabelLM, CheckedSentenceAsLabel, AddCheckedSentence
label_desc: Use image node_id 2 for calling the WoiChunkRetrievedDocs obj's underlying member method code with example usage: obj.message_mutation(message) and returns: chunk_docs_in_message