class_docstr: *LibriTTS* :cite:`Zen2019LibriTTSAC` dataset.
  
  Args:
      root (str or Path): Path to the directory where the dataset is found or downloaded.
      url (str, optional): The URL to download the dataset from,
          or the type of the dataset to dowload.
          Allowed type values are ``"dev-clean"``, ``"dev-other"``, ``"test-clean"``,
          ``"test-other"``, ``"train-clean-100"``, ``"train-clean-360"`` and
          ``"train-other-500"``. (default: ``"train-clean-100"``)
      folder_in_archive (str, optional):
          The top-level directory of the dataset. (default: ``"LibriTTS"``)
      download (bool, optional):
          Whether to download the dataset if it is not found at root path. (default: ``False``).
code: def __len__(self) -> int:
      return len(self._walker)
  
file_path: audio/src/torchaudio/datasets/libritts.py
imports: import os
  from pathlib import Path
  from typing import Tuple, Union
  import torchaudio
  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
label_desc: Use image node_id 3 for calling the LIBRITTS obj's underlying member method code with example usage: obj.__len__() and returns: len