code: def test_sobol_GPEI_strategy_batches(self) -> None:
      mock_GPEI_gen = self.mock_torch_model_bridge.return_value.gen
      mock_GPEI_gen.return_value = GeneratorRun(
          arms=[
              Arm(parameters={"x1": 1, "x2": 2}),
              Arm(parameters={"x1": 3, "x2": 4}),
          ]
      )
      exp = get_branin_experiment()
      sobol_GPEI_generation_strategy = GenerationStrategy(
          name="Sobol+GPEI",
          steps=[
              GenerationStep(
                  model=Models.SOBOL,
                  num_trials=1,
                  model_kwargs=self.step_model_kwargs,
              ),
              GenerationStep(
                  model=Models.GPEI,
                  num_trials=6,
                  model_kwargs=self.step_model_kwargs,
              ),
          ],
      )
      self.assertEqual(
          sobol_GPEI_generation_strategy.name, "Sobol+GPEI"
      )
      self.assertEqual(
          sobol_GPEI_generation_strategy.model_transitions, [1]
      )
      gr = sobol_GPEI_generation_strategy.gen(exp, n=2)
      exp.new_batch_trial(generator_run=gr).run()
      for i in range(1, 8):
          if i == 7:
              # Check completeness error message.
              with self.assertRaises(GenerationStrategyCompleted):
                  g = sobol_GPEI_generation_strategy.gen(exp, n=2)
          else:
              g = sobol_GPEI_generation_strategy.gen(exp, n=2)
          exp.new_batch_trial(generator_run=g).run()
      self.assertIsInstance(
          sobol_GPEI_generation_strategy.model, TorchModelBridge
      )
  
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 17 for calling the TestGenerationStrategy obj's underlying member method code with example usage: obj.test_sobol_GPEI_strategy_batches() without return types