class_docstr: Dropout Polyencoder Agent.
  
  Overrides score_candidates to, sometimes, score candidates in the bi-encoder method.
docstr: Encode context representation.
docstr_tok: ["Encode","context","representation","."]
code: def get_ctxt_rep(
      self, batch: Batch
  ) -> Tuple[torch.Tensor, torch.BoolTensor]:
      """
      Encode context representation.
      """
      if self.use_codes:
          ctxt_rep, ctxt_rep_mask, _ = self.model(
              **self._model_context_input(batch)
          )
      else:
          # In dataparallel, the model is the `model.module`
          model = (
              self.model.module
              if hasattr(self.model, "module")
              else self.model
          )
          model.type = "n_first"
          ctxt_rep, ctxt_rep_mask, _ = self.model(
              **self._model_context_input(batch)
          )
          model.type = self.opt["polyencoder_type"]
  
      return ctxt_rep, ctxt_rep_mask
  
file_path: ParlAI/parlai/agents/transformer/dropout_poly.py
imports: from parlai.core.params import ParlaiParser
  from parlai.agents.transformer.polyencoder import PolyencoderAgent
  from parlai.core.opt import Opt
  from parlai.core.torch_agent import Batch
  import random
  import torch
  from typing import Optional, Tuple
label_desc: Use image node_id 3 for calling the DropoutPolyAgent obj's underlying member method code with example usage: obj.get_ctxt_rep(batch) and returns: ctxt_rep,  ctxt_rep_mask