class_docstr: *Tedlium* :cite:`rousseau2012tedlium` dataset (releases 1,2 and 3).
  
  Args:
      root (str or Path): Path to the directory where the dataset is found or downloaded.
      release (str, optional): Release version.
          Allowed values are ``"release1"``, ``"release2"`` or ``"release3"``.
          (default: ``"release1"``).
      subset (str, optional): The subset of dataset to use. Valid options are ``"train"``, ``"dev"``,
          and ``"test"``. Defaults to ``"train"``.
      download (bool, optional):
          Whether to download the dataset if it is not found at root path. (default: ``False``).
      audio_ext (str, optional): extension for audio file (default: ``".sph"``)
docstr: TEDLIUM dataset custom function overwritting len default behaviour.
  
  Returns:
      int: TEDLIUM dataset length
docstr_tok: ["TEDLIUM","dataset","custom","function","overwritting","len","default","behaviour",".","Returns",":","int",":","TEDLIUM","dataset","length"]
code: def __len__(self) -> int:
      """TEDLIUM dataset custom function overwritting len default behaviour.
  
      Returns:
          int: TEDLIUM dataset length
      """
      return len(self._filelist)
  
file_path: audio/src/torchaudio/datasets/tedlium.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 5 for calling the TEDLIUM obj's underlying member method code with example usage: obj.__len__() and returns: len