class_docstr: Megatron T5 pretraining
class_docstr_tok: ["Megatron","T5","pretraining"]
docstr: allows child classes to add kwargs to dataset building
docstr_tok: ["allows","child","classes","to","add","kwargs","to","dataset","building"]
code: def _build_train_valid_test_datasets_kwargs(self):
      """allows child classes to add kwargs to dataset building"""
      return dict(
          max_seq_length_dec=self._cfg.data.seq_length_dec,
      )
  
imports: import enum
  import math
  from omegaconf.dictconfig import DictConfig
  from pytorch_lightning.trainer.trainer import Trainer
  from nemo.collections.nlp.data.language_modeling.megatron.dataset_utils import build_train_valid_test_datasets
  from nemo.collections.nlp.models.language_modeling.megatron_lm_encoder_decoder_model import MegatronLMEncoderDecoderModel
  from nemo.utils import logging
label_desc: Use image node_id 4 for calling the MegatronT5Model obj's underlying member method code with example usage: obj._build_train_valid_test_datasets_kwargs() and returns: dict