code: def setUp(self):
      self.model = AutoModelForCausalLMWithValueHead.from_pretrained(
          "trl-internal-testing/tiny-random-GPT2LMHeadModel"
      )
      self.test_input = torch.tensor([[0, 1, 2, 3]])
      self.optimizer = torch.optim.AdamW(self.model.parameters(), lr=1)
      self.layer_format = (
          "pretrained_model.transformer.h.{layer}.attn.c_attn.weight"
      )
  
imports: import gc
  import tempfile
  import unittest
  import torch
  from transformers import AutoModel, AutoModelForCausalLM, AutoModelForSeq2SeqLM
  from trl import AutoModelForCausalLMWithValueHead, AutoModelForSeq2SeqLMWithValueHead, create_reference_model
label_desc: Use image node_id 1 for calling the ReferenceModelTest obj's underlying member method code with example usage: obj.setUp() without return types