class_docstr: Tests are in order with the design doc.
code: def test_generation_config_overwrite(self, config1, config2):
      # Generation config
      model = generative_models.GenerativeModel(
          "gemini-m", generation_config=config1
      )
  
      self.responses["generate_content"] = [
          simple_response(" world!"),
          simple_response(" world!"),
      ]
  
      _ = model.generate_content("hello")
      self.assertEqual(
          self.observed_requests[-1].generation_config.temperature, 0.0
      )
  
      _ = model.generate_content("hello", generation_config=config2)
      self.assertEqual(
          self.observed_requests[-1].generation_config.temperature, 0.5
      )
  
imports: import collections
  from collections.abc import Iterable
  import copy
  import pathlib
  import unittest.mock
  from absl.testing import absltest
  from absl.testing import parameterized
  import google.ai.generativelanguage
  from google.generativeai import client
  from google.generativeai import generative_models
  from google.generativeai.types import content_types
  from google.generativeai.types import generation_types
  import PIL.Image
label_desc: Use image node_id 4 for calling the CUJTests obj's underlying member method code with example usage: obj.test_generation_config_overwrite(config1, config2) without return types