code: def validation_step(self, batch, batch_idx):
      return self._step(batch, batch_idx, "val")
  
imports: import logging
  import math
  from collections import namedtuple
  from typing import List, Tuple
  import sentencepiece
  import torch
  import torchaudio
  from pytorch_lightning import LightningModule
  from torchaudio.prototype.models import conformer_rnnt_biasing_base, Hypothesis, RNNTBeamSearchBiasing
label_desc: Use image node_id 6 for calling the ConformerRNNTModule obj's underlying member method code with example usage: obj.validation_step(batch, batch_idx) and returns: self