code: def _get_speaker_to_id(self):
      speaker_to_id = None
      speaker_set_filename = self.data_cfg.config.get(
          "speaker_set_filename"
      )
      if speaker_set_filename is not None:
          speaker_set_path = Path(self.args.data) / speaker_set_filename
          with open(speaker_set_path) as f:
              speaker_to_id = {r.strip(): i for i, r in enumerate(f)}
      return speaker_to_id
  
imports: import logging
  from argparse import Namespace
  from pathlib import Path
  from typing import List
  from fairseq.data import Dictionary, encoders
  from fairseq.data.audio.audio_utils import get_features_or_waveform
  from fairseq.data.audio.data_cfg import MultitaskConfig
  from fairseq.data.audio.speech_to_text_dataset import S2TDataConfig, SpeechToTextDataset, SpeechToTextDatasetCreator, TextTargetMultitaskData
  from fairseq.tasks import LegacyFairseqTask, register_task
label_desc: Use image node_id 3 for calling the SpeechToTextTask obj's underlying member method code with example usage: obj._get_speaker_to_id() and returns: speaker_to_id