class_docstr: Megatron NMT training
class_docstr_tok: ["Megatron","NMT","training"]
code: def setup_training_data(
      self, train_data_config: Optional[DictConfig]
  ):
      if hasattr(self, "_train_ds"):
          consumed_samples = self.compute_consumed_samples(0)
          self._train_dl = self._setup_megatron_dataloader_from_config(
              cfg=train_data_config,
              dataset=self._train_ds,
              consumed_samples=consumed_samples,
          )
  
imports: import enum
  import itertools
  import random
  from typing import List, Optional
  import numpy
  import torch
  from omegaconf.dictconfig import DictConfig
  from omegaconf.listconfig import ListConfig
  from pytorch_lightning.trainer.trainer import Trainer
  from sacrebleu import corpus_bleu
  from nemo.collections.nlp.data.common.sequence_to_sequence_dataset import BinarizedMemmapSequenceToSequenceDataset, TextMemmapSequenceToSequenceDataset
  from nemo.collections.nlp.data.language_modeling.megatron.base_dataset_utils import get_datasets_weights_and_num_samples
  from nemo.collections.nlp.data.language_modeling.megatron.blendable_dataset import BlendableDataset
  from nemo.collections.nlp.data.language_modeling.megatron.megatron_batch_samplers import MegatronPretrainingBatchSampler
  from nemo.collections.nlp.data.language_modeling.megatron.xlm_dataset import BinarizedMemmapCrossLingualMLMAndTranslationDataset, TextMemmapCrossLingualMLMAndTranslationDataset
  from nemo.collections.nlp.models.language_modeling.megatron_lm_encoder_decoder_model import MegatronLMEncoderDecoderModel
  from nemo.collections.nlp.models.language_modeling.megatron_t5_model import MegatronT5Model
  from nemo.collections.nlp.models.machine_translation.mt_enc_dec_model import MTEncDecModel
  from nemo.collections.nlp.modules.common.megatron.megatron_export import DecEmb, EncEmb, TokensHeadEmb
  from nemo.collections.nlp.modules.common.megatron.utils import get_iterator_k_split
  from nemo.collections.nlp.parts.nlp_overrides import GlobalBatchDataFetcher
  from nemo.collections.nlp.parts.utils_funcs import get_last_rank
  from nemo.core.classes import Exportable
  from nemo.utils import AppState, logging, timers
label_desc: Use image node_id 18 for calling the MegatronNMTModel obj's underlying member method code with example usage: obj.setup_training_data(train_data_config) without return types