code: def optional_data_names(
      cls, train: bool = True, inference: bool = False
  ) -> Tuple[str, ...]:
      # (Note: jiatong): no optional data names for now
      retval = ()
      assert check_return_type(retval)
      return retval
  
imports: import argparse
  from typing import Callable, Collection, Dict, List, Optional, Tuple
  import numpy
  import torch
  from typeguard import check_argument_types, check_return_type
  from espnet2.asr.encoder.abs_encoder import AbsEncoder
  from espnet2.asr.encoder.conformer_encoder import ConformerEncoder
  from espnet2.asr.encoder.rnn_encoder import RNNEncoder
  from espnet2.asr.encoder.transformer_encoder import TransformerEncoder
  from espnet2.asr.frontend.abs_frontend import AbsFrontend
  from espnet2.asr.frontend.default import DefaultFrontend
  from espnet2.asr.frontend.s3prl import S3prlFrontend
  from espnet2.asr.frontend.windowing import SlidingWindow
  from espnet2.asr.specaug.abs_specaug import AbsSpecAug
  from espnet2.asr.specaug.specaug import SpecAug
  from espnet2.diar.attractor.abs_attractor import AbsAttractor
  from espnet2.diar.attractor.rnn_attractor import RnnAttractor
  from espnet2.diar.decoder.abs_decoder import AbsDecoder
  from espnet2.diar.decoder.linear_decoder import LinearDecoder
  from espnet2.diar.espnet_model import ESPnetDiarizationModel
  from espnet2.layers.abs_normalize import AbsNormalize
  from espnet2.layers.global_mvn import GlobalMVN
  from espnet2.layers.label_aggregation import LabelAggregate
  from espnet2.layers.utterance_mvn import UtteranceMVN
  from espnet2.tasks.abs_task import AbsTask
  from espnet2.torch_utils.initialize import initialize
  from espnet2.train.class_choices import ClassChoices
  from espnet2.train.collate_fn import CommonCollateFn
  from espnet2.train.preprocessor import CommonPreprocessor
  from espnet2.train.trainer import Trainer
  from espnet2.utils.get_default_kwargs import get_default_kwargs
  from espnet2.utils.nested_dict_action import NestedDictAction
  from espnet2.utils.types import int_or_none, str2bool, str_or_none
label_desc: Use image node_id 5 for calling the DiarizationTask obj's underlying member method code with example usage: obj.optional_data_names(cls, train, inference) and returns: retval