code: def __getitem__(self, index: int) -> SpeechToSpeechDatasetItem:
      source = self._get_source_audio(index)
  
      tgt_lang_tag = None
      if self.cfg.prepend_tgt_lang_tag_as_bos:
          # prepend_tgt_lang_tag_as_bos: put tgt_lang_tag as bos of target
          tgt_lang_tag = self.get_lang_tag_idx(
              self.tgt_langs[index], self.tgt_dict
          )
  
      if not self.target_is_code:
          target = get_features_or_waveform(self.tgt_audio_paths[index])
          target = torch.from_numpy(target).float()
          target = self.pack_frames(target)
      else:
          target = self.tgt_dict.encode_line(
              self.tgt_audio_paths[index],
              add_if_not_exist=False,
              append_eos=True,
          ).long()
          if self.n_frames_per_step > 1:
              n_tgt_frame = target.size(0) - 1  # exclude <eos>
              keep_n_tgt_frame = (
                  n_tgt_frame - n_tgt_frame % self.n_frames_per_step
              )
              target = torch.cat(
                  (
                      target[:keep_n_tgt_frame],
                      target.new_full((1,), self.tgt_dict.eos()),
                  ),
                  dim=0,
              )
  
      if self.tgt_speakers:
          tgt_spk = get_features_or_waveform(self.tgt_speakers[index])
          tgt_spk = torch.from_numpy(tgt_spk).float()
      else:
          tgt_spk = torch.FloatTensor([])
  
      return SpeechToSpeechDatasetItem(
          index=index,
          source=source,
          target=target,
          target_speaker=tgt_spk,
          tgt_lang_tag=tgt_lang_tag,
      )
  
imports: import logging
  from dataclasses import dataclass
  from pathlib import Path
  from typing import Dict, List, Optional, Tuple
  import torch
  from fairseq.data import ConcatDataset, Dictionary
  from fairseq.data import data_utils
  from fairseq.data.audio.audio_utils import get_features_or_waveform
  from fairseq.data.audio.data_cfg import S2SDataConfig
  from fairseq.data.audio.speech_to_text_dataset import SpeechToTextDataset, SpeechToTextDatasetCreator, TextTargetMultitaskData, _collate_frames
label_desc: Use image node_id 3 for calling the SpeechToSpeechDataset obj's underlying member method code with example usage: obj.__getitem__(index) and returns: SpeechToSpeechDatasetItem