class_docstr: A wrapper class for testing PPOTrainer
class_docstr_tok: ["A","wrapper","class","for","testing","PPOTrainer"]
code: def setUpClass(cls):
      set_seed(42)
      cls._token = CI_HUB_USER_TOKEN
      cls._api = HfApi(endpoint=CI_HUB_ENDPOINT)
      HfFolder.save_token(CI_HUB_USER_TOKEN)
  
      # model_id
      cls.model_id = "trl-internal-testing/dummy-GPT2-correct-vocab"
  
      # get models and tokenizer
      cls.gpt2_model = (
          AutoModelForCausalLMWithValueHead.from_pretrained(
              cls.model_id
          )
      )
      cls.gpt2_model_ref = (
          AutoModelForCausalLMWithValueHead.from_pretrained(
              cls.model_id
          )
      )
      cls.gpt2_tokenizer = AutoTokenizer.from_pretrained(cls.model_id)
  
      cls.gpt2_tokenizer.pad_token = cls.gpt2_tokenizer.eos_token
  
      # get bloom as right padding examples:
      model_id = (
          "trl-internal-testing/tiny-BloomForCausalLM-correct-vocab"
      )
      cls.bloom_model = (
          AutoModelForCausalLMWithValueHead.from_pretrained(model_id)
      )
      cls.bloom_tokenizer = AutoTokenizer.from_pretrained(model_id)
  
      model_id = "trl-internal-testing/tiny-T5ForConditionalGeneration-correct-vocab"
      cls.t5_model = AutoModelForSeq2SeqLMWithValueHead.from_pretrained(
          model_id
      )
      cls.t5_tokenizer = AutoTokenizer.from_pretrained(model_id)
  
      # initialize trainer
      cls.ppo_config = PPOConfig(
          batch_size=2, mini_batch_size=1, log_with=None
      )
  
imports: import copy
  import fnmatch
  import gc
  import re
  import tempfile
  import unittest
  import pytest
  import torch
  from huggingface_hub import HfApi, HfFolder, delete_repo
  from parameterized import parameterized
  from pytest import mark
  from requests.exceptions import HTTPError
  from transformers import AutoTokenizer
  from trl import AutoModelForCausalLMWithValueHead, AutoModelForSeq2SeqLMWithValueHead, PPOConfig, PPOTrainer, set_seed
  from trl.core import respond_to_batch
  from .testing_constants import CI_HUB_ENDPOINT, CI_HUB_USER, CI_HUB_USER_TOKEN
  from .testing_utils import require_peft, require_torch_multi_gpu
label_desc: Use image node_id 1 for calling the PPOTrainerTester obj's underlying member method code with example usage: obj.setUpClass(cls) without return types