code: def test_model_list(self):
      tkwargs = {"device": self.device, "dtype": torch.double}
      m1 = GenericDeterministicModel(lambda X: X[-1:], num_outputs=1)
      m2 = GenericDeterministicModel(lambda X: X[-2:], num_outputs=2)
      model = ModelList(m1, m2)
      self.assertEqual(model.num_outputs, 3)
      # test _get_group_subset_indices
      gsi = model._get_group_subset_indices(idcs=None)
      self.assertEqual(len(gsi), 2)
      self.assertIsNone(gsi[0])
      self.assertIsNone(gsi[1])
      gsi = model._get_group_subset_indices(idcs=[0, 2])
      self.assertEqual(len(gsi), 2)
      self.assertEqual(gsi[0], [0])
      self.assertEqual(gsi[1], [1])
      # test subset_model
      m_sub = model.subset_output(idcs=[0, 1])
      self.assertIsInstance(m_sub, ModelList)
      self.assertEqual(m_sub.num_outputs, 2)
      m_sub = model.subset_output(idcs=[1, 2])
      self.assertIsInstance(m_sub, GenericDeterministicModel)
      self.assertEqual(m_sub.num_outputs, 2)
      # test posterior
      X = torch.rand(2, 2, **tkwargs)
      p = model.posterior(X=X)
      self.assertIsInstance(p, PosteriorList)
      # test batch shape
      m1 = GenericDeterministicModelWithBatchShape(
          lambda X: X[-1:], num_outputs=1
      )
      m2 = GenericDeterministicModelWithBatchShape(
          lambda X: X[-2:], num_outputs=2
      )
      model = ModelList(m1, m2)
      m1._batch_shape = torch.Size([2])
      m2._batch_shape = torch.Size([2])
      self.assertEqual(model.batch_shape, torch.Size([2]))
      m2._batch_shape = torch.Size([3])
      with self.assertRaisesRegex(
          NotImplementedError,
          "is only supported if all constituent models have the same `batch_shape`",
      ):
          model.batch_shape
  
imports: from unittest.mock import patch
  import torch
  from botorch.acquisition.objective import PosteriorTransform
  from botorch.exceptions.errors import InputDataError
  from botorch.models.deterministic import GenericDeterministicModel
  from botorch.models.model import Model, ModelDict, ModelList
  from botorch.models.utils import parse_training_data
  from botorch.posteriors.deterministic import DeterministicPosterior
  from botorch.posteriors.posterior_list import PosteriorList
  from botorch.utils.testing import BotorchTestCase, MockModel, MockPosterior
label_desc: Use image node_id 4 for calling the TestBaseModel obj's underlying member method code with example usage: obj.test_model_list() without return types