code: def _download_librispeech(root, url):
      base_url = "http://www.openslr.org/resources/12/"
      ext_archive = ".tar.gz"
  
      filename = url + ext_archive
      archive = os.path.join(root, filename)
      download_url = os.path.join(base_url, filename)
      if not os.path.isfile(archive):
          checksum = _CHECKSUMS.get(download_url, None)
          download_url_to_file(
              download_url, archive, hash_prefix=checksum
          )
      _extract_tar(archive)
  
file_path: audio/src/torchaudio/datasets/librispeech.py
imports: import os
  from pathlib import Path
  from typing import Tuple, Union
  from torch import Tensor
  from torch.utils.data import Dataset
  from torchaudio._internal import download_url_to_file
  from torchaudio.datasets.utils import _extract_tar, _load_waveform
label_desc: Use image node_id 1 for calling a global function with example usage: _download_librispeech(root, url) without return types