code: def build_generator_dual_decoder(
      self,
      models,
      args,
      extra_gen_cls_kwargs,
  ):
      from examples.speech_to_speech.unity.sequence_generator_multi_decoder import (
          MultiDecoderSequenceGenerator,
      )
  
      lang_token_ids_aux = {
          i
          for s, i in self.tgt_dict_mt.indices.items()
          if TextTargetMultitaskData.is_lang_tag(s)
      }
  
      extra_gen_cls_kwargs["symbols_to_strip_from_output"].update(
          lang_token_ids_aux
      )
  
      eos_id_mt = (
          self.tgt_dict_mt.index(self.eos_token_mt)
          if self.eos_token_mt
          else None
      )
      assert eos_id_mt != self.tgt_dict_mt.unk()
      extra_gen_cls_kwargs["eos_mt"] = eos_id_mt
  
      return MultiDecoderSequenceGenerator(
          models,
          self.target_dictionary,
          self.target_dictionary_mt,
          beam_size=max(1, getattr(args, "beam", 1)),
          beam_size_mt=max(1, getattr(args, "beam_mt", 1)),
          max_len_a=getattr(args, "max_len_a", 0),
          max_len_b=getattr(args, "max_len_b", 200),
          max_len_a_mt=getattr(args, "max_len_a_mt", 0),
          max_len_b_mt=getattr(args, "max_len_b_mt", 0),
          min_len=getattr(args, "min_len", 1),
          normalize_scores=(not getattr(args, "unnormalized", False)),
          len_penalty=getattr(args, "lenpen", 1),
          len_penalty_mt=getattr(args, "lenpen_mt", 1),
          unk_penalty=getattr(args, "unkpen", 0),
          temperature=getattr(args, "temperature", 1.0),
          match_source_len=getattr(args, "match_source_len", False),
          no_repeat_ngram_size=getattr(args, "no_repeat_ngram_size", 0),
          **extra_gen_cls_kwargs,
      )
  
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 12 for calling the SpeechToTextTask obj's underlying member method code with example usage: obj.build_generator_dual_decoder(models, args, extra_gen_cls_kwargs) and returns: MultiDecoderSequenceGenerator