class_docstr: GPT2 with Retriever Model.
  
  A GPT2 model that receives documents from a retriever.
class_docstr_tok: ["GPT2","with","Retriever","Model",".","A","GPT2","model","that","receives","documents","from","a","retriever","."]
docstr: Override to account for left-padded input.
docstr_tok: ["Override","to","account","for","left-padded","input","."]
code: def concat_docs_and_input(
      self,
      input: torch.LongTensor,
      input_lengths: torch.LongTensor,
      top_docs: List[List[Document]],
      max_num_docs: int,
      right_padded: bool = True,
  ) -> torch.LongTensor:
      """
      Override to account for left-padded input.
      """
      return super().concat_docs_and_input(
          input,
          input_lengths,
          top_docs,
          max_num_docs,
          right_padded=False,
      )
  
imports: from typing import Optional, Type, Tuple, List, Dict, Any
  import torch
  import torch.nn
  from parlai.agents.fid.fid import FidModel, concat_enc_outs
  from parlai.agents.hugging_face.gpt2 import GPT2Decoder, Gpt2Agent
  from parlai.agents.rag.args import RetrieverType
  from parlai.agents.rag.modules import RagModel
  from parlai.agents.rag.retrievers import Document, BLANK_DOC, SearchQuerySearchEngineRetriever, retriever_factory, RagRetriever
  from parlai.core.dict import DictionaryAgent
  from parlai.core.opt import Opt
  import parlai.utils.logging
  from projects.seeker.agents.seeker_modules import ComboFidSearchQuerySearchEngineRetriever
  from projects.seeker.agents.seeker_modules import combo_fid_retriever_factory, interleave_fid_combo_outputs, ComboFidModel
label_desc: Use image node_id 7 for calling the GPT2WithRetrieverModel obj's underlying member method code with example usage: obj.concat_docs_and_input(input, input_lengths, top_docs, max_num_docs, right_padded) and returns: super