class_docstr: BlenderBot2RagModel with seq2seq_encoder = ShiftInvariantRagEncoder
class_docstr_tok: ["BlenderBot2RagModel","with","seq2seq_encoder","=","ShiftInvariantRagEncoder"]
code: def build_encoder(cls, opt: Opt, *args, **kwargs):
      return LongRagModel.build_encoder(opt, *args, **kwargs)
  
imports: from typing import Optional, Union
  from parlai.core.message import Message
  from parlai.core.opt import Opt
  from parlai.core.params import ParlaiParser
  from projects.blenderbot2.agents.sub_modules import KnowledgeAccessMethod
  from projects.blenderbot2.agents.modules import T5BlenderBot2RagModel, BlenderBot2RagModel, T5BlenderBot2FidModel, BlenderBot2FidModel, BlenderBot2FidModelMixin
  import torch
  from projects.blenderbot2.agents.blenderbot2 import BlenderBot2RagAgent
  from .long_rag import LongRagAgent, LongRagModel, LongFidAgent, LongFidModel
label_desc: Use image node_id 1 for calling the MemoryLongRagModel obj's underlying member method code with example usage: obj.build_encoder(cls, opt) and returns: LongRagModel