class_docstr: DialoGPT Decoder.
  
  This decoder is initialized with the pretrained model from Hugging Face.
class_docstr_tok: ["DialoGPT","Decoder",".","This","decoder","is","initialized","with","the","pretrained","model","from","Hugging","Face","."]
code: def _get_special_tokens(opt, dict):
      null_idx = dict.null_idx
      if (
          opt.get("batchsize", 1) == 1
          and not opt["add_special_tokens"]
          and null_idx == dict.end_idx
      ):
          # get around the dual usage of end_idx that would otherwise mask endtoken during forward pass.
          null_idx = -1
      return null_idx, dict.start_idx, dict.end_idx
  
file_path: ParlAI/parlai/agents/hugging_face/dialogpt.py
imports: from typing import Optional
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  from parlai.agents.hugging_face.dict import DialoGPTDictionaryAgent
  from parlai.agents.hugging_face.gpt2 import Gpt2Agent, GPT2Decoder, HFGPT2Model
  from parlai.utils.misc import warn_once
label_desc: Use image node_id 2 for calling the DialoGPTDecoder obj's underlying member method code with example usage: obj._get_special_tokens(opt, dict) and returns: null_idx,  dict,  dict