class_docstr: *CommonVoice* :cite:`ardila2020common` dataset.
  
  Args:
      root (str or Path): Path to the directory where the dataset is located.
           (Where the ``tsv`` file is present.)
      tsv (str, optional):
          The name of the tsv file used to construct the metadata, such as
          ``"train.tsv"``, ``"test.tsv"``, ``"dev.tsv"``, ``"invalidated.tsv"``,
          ``"validated.tsv"`` and ``"other.tsv"``. (default: ``"train.tsv"``)
class_docstr_tok: ["*","CommonVoice","*",":","cite",":","`","ardila2020common","`","dataset",".","Args",":","root","(","str","or","Path",")",":","Path","to","the","directory","where","the","dataset","is","located",".","(","Where","the","``","tsv","``","file","is","present",".",")","tsv","(","str",",","optional",")",":","The","name","of","the","tsv","file","used","to","construct","the","metadata",",","such","as","``","``","train.tsv","''","``",",","``","``","test.tsv","''","``",",","``","``","dev.tsv","''","``",",","``","``","invalidated.tsv","''","``",",","``","``","validated.tsv","''","``","and","``","``","other.tsv","''","``",".","(","default",":","``","``","train.tsv","''","``",")"]
code: def __len__(self) -> int:
      return len(self._walker)
  
file_path: audio/src/torchaudio/datasets/commonvoice.py
imports: import csv
  import os
  from pathlib import Path
  from typing import Dict, List, Tuple, Union
  import torchaudio
  from torch import Tensor
  from torch.utils.data import Dataset
label_desc: Use image node_id 3 for calling the COMMONVOICE obj's underlying member method code with example usage: obj.__len__() and returns: len