code: def optimizer_step(self, optimizer, model, update_num):
      if hasattr(model, "get_groups_for_update"):
          groups = model.get_groups_for_update(update_num)
          optimizer.step(groups={groups})
      else:
          optimizer.step()
  
imports: from dataclasses import dataclass, field
  import logging
  import math
  import os
  from typing import Optional
  import torch
  from fairseq.logging import metrics
  from fairseq.tasks import FairseqTask, register_task
  from ..data import ExtractedFeaturesDataset, RandomInputDataset
  from fairseq.data import Dictionary, data_utils, StripTokenDataset
  from fairseq.dataclass import FairseqDataclass
  from fairseq.distributed.utils import get_data_parallel_world_size
  from omegaconf import MISSING
  from examples.speech_recognition.kaldi.kaldi_decoder import KaldiDecoder, KaldiDecoderConfig
label_desc: Use image node_id 3 for calling the UnpairedAudioText obj's underlying member method code with example usage: obj.optimizer_step(optimizer, model, update_num) without return types