docstr: Checks that generation strategy works with custom factory functions.
  No information about the model should be saved on generator run.
code: def test_with_factory_function(self) -> None:
      """Checks that generation strategy works with custom factory functions.
      No information about the model should be saved on generator run.
      """
  
      def get_sobol(search_space: SearchSpace) -> RandomModelBridge:
          return RandomModelBridge(
              search_space=search_space,
              model=SobolGenerator(),
              transforms=Cont_X_trans,
          )
  
      exp = get_branin_experiment()
      sobol_generation_strategy = GenerationStrategy(
          steps=[GenerationStep(model=get_sobol, num_trials=5)]
      )
      g = sobol_generation_strategy.gen(exp)
      self.assertIsInstance(
          sobol_generation_strategy.model, RandomModelBridge
      )
      self.assertIsNone(g._model_key)
      self.assertIsNone(g._model_kwargs)
      self.assertIsNone(g._bridge_kwargs)
  
imports: import logging
  from typing import cast, List
  from unittest import mock
  from unittest.mock import MagicMock, patch
  from ax.core.arm import Arm
  from ax.core.base_trial import TrialStatus
  from ax.core.experiment import Experiment
  from ax.core.generator_run import GeneratorRun
  from ax.core.observation import ObservationFeatures
  from ax.core.parameter import ChoiceParameter, FixedParameter, Parameter, ParameterType
  from ax.core.search_space import SearchSpace
  from ax.core.utils import get_pending_observation_features_based_on_trial_status
  from ax.exceptions.core import DataRequiredError, UnsupportedError, UserInputError
  from ax.exceptions.generation_strategy import GenerationStrategyCompleted, GenerationStrategyMisconfiguredException, GenerationStrategyRepeatedPoints, MaxParallelismReachedException
  from ax.modelbridge.discrete import DiscreteModelBridge
  from ax.modelbridge.factory import get_sobol
  from ax.modelbridge.generation_node import GenerationNode
  from ax.modelbridge.generation_strategy import GenerationStep, GenerationStrategy
  from ax.modelbridge.model_spec import ModelSpec
  from ax.modelbridge.random import RandomModelBridge
  from ax.modelbridge.registry import Cont_X_trans, MODEL_KEY_TO_MODEL_SETUP, Models
  from ax.modelbridge.torch import TorchModelBridge
  from ax.modelbridge.transition_criterion import MaxGenerationParallelism, MaxTrials, MinTrials
  from ax.models.random.sobol import SobolGenerator
  from ax.utils.common.equality import same_elements
  from ax.utils.common.mock import mock_patch_method_original
  from ax.utils.common.testutils import TestCase
  from ax.utils.common.typeutils import not_none
  from ax.utils.testing.core_stubs import get_branin_data, get_branin_experiment, get_choice_parameter, get_data, get_experiment_with_multi_objective, get_hierarchical_search_space_experiment
label_desc: Use image node_id 18 for calling the TestGenerationStrategy obj's underlying member method code with example usage: obj.test_with_factory_function() and returns: RandomModelBridge