code: def test_fixed_features_is_from_model_to_gen_from(self) -> None:
      self.model_selection_node.model_specs[
          0
      ].fixed_features = ObservationFeatures(parameters={"x": 0})
      self.model_selection_node.model_specs[
          1
      ].fixed_features = ObservationFeatures(parameters={"x": 1})
      self.assertEqual(
          self.model_selection_node.fixed_features,
          self.model_selection_node.model_spec_to_gen_from.fixed_features,
      )
  
imports: import logging
  from logging import Logger
  from unittest.mock import patch, PropertyMock
  from ax.core.base_trial import TrialStatus
  from ax.core.observation import ObservationFeatures
  from ax.exceptions.core import UserInputError
  from ax.modelbridge.cross_validation import DiagnosticCriterion, MetricAggregation, SingleDiagnosticBestModelSelector
  from ax.modelbridge.factory import get_sobol
  from ax.modelbridge.generation_node import GenerationNode, GenerationStep
  from ax.modelbridge.model_spec import FactoryFunctionModelSpec, ModelSpec
  from ax.modelbridge.registry import Models
  from ax.modelbridge.transition_criterion import MaxTrials
  from ax.utils.common.logger import get_logger
  from ax.utils.common.testutils import TestCase
  from ax.utils.testing.core_stubs import get_branin_experiment
  from ax.utils.testing.mock import fast_botorch_optimize
label_desc: Use image node_id 3 for calling the TestGenerationNodeWithBestModelSelector obj's underlying member method code with example usage: obj.test_fixed_features_is_from_model_to_gen_from() without return types