code: def _check_timit_folders(uppercase, data_folder):
      """
      Check if the data folder actually contains the TIMIT dataset.
  
      If not, raises an error.
  
      Returns
      -------
      None
  
      Raises
      ------
      FileNotFoundError
          If data folder doesn't contain TIMIT dataset.
      """
  
      # Creating checking string wrt to lower or uppercase
      if uppercase:
          test_str = "/TEST/DR1"
          train_str = "/TRAIN/DR1"
      else:
          test_str = "/test/dr1"
          train_str = "/train/dr1"
  
      # Checking test/dr1
      if not os.path.exists(data_folder + test_str):
          err_msg = (
              "the folder %s does not exist (it is expected in "
              "the TIMIT dataset)" % (data_folder + test_str)
          )
          raise FileNotFoundError(err_msg)
  
      # Checking train/dr1
      if not os.path.exists(data_folder + train_str):
          err_msg = (
              "the folder %s does not exist (it is expected in "
              "the TIMIT dataset)" % (data_folder + train_str)
          )
          raise FileNotFoundError(err_msg)
  
file_path: speechbrain/recipes/TIMIT/ASR/seq2seq/timit_prepare.py
imports: import os
  import json
  import logging
  from speechbrain.utils.data_utils import get_all_files
  from speechbrain.dataio.dataio import read_audio
label_desc: Use image node_id 7 for calling a global function with example usage: _check_timit_folders(uppercase, data_folder) without return types