code: def __len__(self):
      return len(self.dataset)
  
imports: import unittest
  import torch
  import tqdm
  import torchaudio
  import pathlib
  import jiwer
  import os
  import numpy
  from whisper.normalizers import EnglishTextNormalizer
  from examples.whisper import init_whisper, transcribe_waveform
label_desc: Use image node_id 2 for calling the LibriSpeech obj's underlying member method code with example usage: obj.__len__() and returns: len