code: def training_step(self, batch: Batch, batch_idx):
      return self._step(batch, batch_idx, "train")
  
imports: import os
  from functools import partial
  from typing import List
  import sentencepiece
  import torch
  import torchaudio
  from common import Batch, batch_by_token_count, FunctionalModule, GlobalStatsNormalization, piecewise_linear_log, post_process_hypos, spectrogram_transform, WarmupLR
  from pytorch_lightning import LightningModule
  from torchaudio.models import emformer_rnnt_base, RNNTBeamSearch
label_desc: Use image node_id 11 for calling the LibriSpeechRNNTModule obj's underlying member method code with example usage: obj.training_step(batch, batch_idx) and returns: self