code: def valid_step(self, sample, model, criterion):
      for task_name, task_obj in self.multitask_tasks.items():
          if task_name in model.multitask_decoders:
              model.multitask_decoders[task_name].eval()
      loss, sample_size, logging_output = super().valid_step(
          sample, model, criterion
      )
  
      return loss, sample_size, logging_output
  
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 15 for calling the SpeechToTextTask obj's underlying member method code with example usage: obj.valid_step(sample, model, criterion) and returns: loss,  sample_size,  logging_output