class_docstr: Hugging Face GPT2 Agent.
  
  GPT2 is a multi-layer decoder-only Transformer.
  The decoder is initialized with pretrained weights from Hugging Face.
  Read more about this model here
  <https://huggingface.co/transformers/model_doc/gpt2.html>.
  
  GPT2 comes in five sizes: distilgpt2, small, medium, large, XL. Use the
  flag `--gpt2-size` to choose the size.
  
  If you are finetuning the Gpt2 agent as a dialogue agent, be sure
  to run `--add-special-tokens True`. To examine the performance of the
  agent out of the box, run with `--add-special-tokens False`, and make
  sure that the batch size is 1.
class_docstr_tok: ["Hugging","Face","GPT2","Agent",".","GPT2","is","a","multi-layer","decoder-only","Transformer",".","The","decoder","is","initialized","with","pretrained","weights","from","Hugging","Face",".","Read","more","about","this","model","here","<","https",":","\/\/huggingface.co\/transformers\/model_doc\/gpt2.html",">",".","GPT2","comes","in","five","sizes",":","distilgpt2",",","small",",","medium",",","large",",","XL",".","Use","the","flag","`","--","gpt2-size","`","to","choose","the","size",".","If","you","are","finetuning","the","Gpt2","agent","as","a","dialogue","agent",",","be","sure","to","run","`","--","add-special-tokens","True","`",".","To","examine","the","performance","of","the","agent","out","of","the","box",",","run","with","`","--","add-special-tokens","False","`",",","and","make","sure","that","the","batch","size","is","1","."]
docstr: Return the dictionary class that this agent expects to use.
  
  Can be overridden if a more complex dictionary is required.
docstr_tok: ["Return","the","dictionary","class","that","this","agent","expects","to","use",".","Can","be","overridden","if","a","more","complex","dictionary","is","required","."]
code: def dictionary_class():
      """
      Return the dictionary class that this agent expects to use.
  
      Can be overridden if a more complex dictionary is required.
      """
      return Gpt2DictionaryAgent
  
imports: from typing import Optional
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  import os
  import torch
  from parlai.agents.hugging_face.dict import Gpt2DictionaryAgent
  from parlai.core.torch_generator_agent import TorchGeneratorAgent, TorchGeneratorModel
  from parlai.utils.io import PathManager
  from parlai.utils.misc import warn_once
  from parlai.utils.torch import IdentityLayer, padded_tensor
label_desc: Use image node_id 3 for calling the Gpt2Agent obj's underlying member method code with example usage: obj.dictionary_class() and returns: Gpt2DictionaryAgent