class_docstr: Wikipedia gender.
class_docstr_tok: ["Wikipedia","gender","."]
code: def _set_chunk_idx_to_file(self, opt):
      # download wikipedia data
      wiki_opt = deepcopy(opt)
      wiki_opt["task"] = "wikipedia:full"
      build(wiki_opt)
  
      # now divide data into subfolders
      data_folder = self._get_data_folder()
      self.chunk_idx_to_file = {}
      i = 0
      for subdir in os.listdir(data_folder):
          if subdir != "README.md":
              for fle in os.listdir(os.path.join(data_folder, subdir)):
                  self.chunk_idx_to_file[i] = os.path.join(
                      data_folder, subdir, fle
                  )
                  i += 1
  
imports: from typing import Optional
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  from parlai.core.message import Message
  from parlai.core.teachers import ChunkTeacher
  from parlai.tasks.wikipedia.build import build
  from parlai.utils.misc import warn_once
  import parlai.tasks.md_gender.utils
  from copy import deepcopy
  import json
  import os
  import random
  import re
  import spacy
  from typing import List
label_desc: Use image node_id 3 for calling the WikipediaTeacher obj's underlying member method code with example usage: obj._set_chunk_idx_to_file(opt) without return types