code: def _maybe_download_corpora(tmp_dir):
    
    mnli_filename = "MNLI.zip"
    mnli_finalpath = os.path.join(tmp_dir, "MNLI")
    if not tf.gfile.Exists(mnli_finalpath):
      zip_filepath = generator_utils.maybe_download(
          tmp_dir, mnli_filename, _MNLI_URL)
      zip_ref = zipfile.ZipFile(zip_filepath, "r")
      zip_ref.extractall(tmp_dir)
      zip_ref.close()
  
    return mnli_finalpath
docs: Download corpora for multinli.
  
    Args:
      tmp_dir: a string
    Returns:
      a string