code: def batchify(self, obs_batch):
      batch = super().batchify(obs_batch)
      reordered_observations = [
          obs_batch[i] for i in batch.valid_indices
      ]
  
      checked_sentences = []
      for obs in reordered_observations:
          checked_sentence = "{} {} {}".format(
              obs.get("title", ""),
              TOKEN_KNOWLEDGE,
              obs.get("checked_sentence", ""),
          )
          checked_sentences.append(checked_sentence)
  
      batch["checked_sentence"] = checked_sentences
  
      return batch
  
imports: from typing import Optional
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  from itertools import chain
  from functools import lru_cache
  import torch
  import numpy
  from parlai.utils.torch import padded_tensor
  from parlai.utils.misc import round_sigfigs
  from parlai.agents.transformer.transformer import TransformerGeneratorAgent
  from .modules import EndToEndModel
  from parlai.tasks.wizard_of_wikipedia.agents import TOKEN_KNOWLEDGE
label_desc: Use image node_id 2 for calling the _GenericWizardAgent obj's underlying member method code with example usage: obj.batchify(obs_batch) and returns: batch