code: def set_context_encoder_for_training(
      self, ctx_encoder: PreTrainedModel
  ):
      self.rag.context_encoder_training = True
      self.rag.ctx_encoder = ctx_encoder
  
imports: from dataclasses import dataclass
  from typing import Callable, List, Optional, Tuple, Union
  import torch
  from torch import nn
  from ...configuration_utils import PretrainedConfig
  from ...generation_beam_search import BeamSearchScorer
  from ...generation_logits_process import LogitsProcessorList
  from ...generation_stopping_criteria import StoppingCriteriaList
  from ...modeling_outputs import ModelOutput
  from ...modeling_utils import PreTrainedModel
  from ...utils import add_start_docstrings_to_model_forward, logging, replace_return_docstrings
  from .configuration_rag import RagConfig
  from .retrieval_rag import RagRetriever
label_desc: Use image node_id 3 for calling the RagSequenceForGeneration obj's underlying member method code with example usage: obj.set_context_encoder_for_training(ctx_encoder) without return types