code: def __getitem__(self, idx):
      return self.query_data[idx], self.response_data[idx]
  
file_path: trl/tests/test_no_peft.py
imports: import sys
  import unittest
  from unittest.mock import patch
  import torch
  from transformers import AutoModelForCausalLM, AutoTokenizer
  from .testing_utils import is_peft_available, require_peft
label_desc: Use image node_id 3 for calling the DummyDataset obj's underlying member method code with example usage: obj.__getitem__(idx) and returns: self,  self