code: def test_CrossValidate(self, mock_init):
      # pyre-fixme[20]: Argument `model` expected.
      modelbridge = RandomModelBridge()
      modelbridge.transforms = OrderedDict()
      modelbridge.parameters = ["x", "y", "z"]
      with self.assertRaises(NotImplementedError):
          modelbridge._cross_validate(self.search_space, [], [])
  
imports: from collections import OrderedDict
  from unittest import mock
  import numpy
  from ax.core.observation import ObservationFeatures
  from ax.core.parameter import ParameterType, RangeParameter
  from ax.core.parameter_constraint import OrderConstraint, SumConstraint
  from ax.core.search_space import SearchSpace
  from ax.exceptions.core import SearchSpaceExhausted
  from ax.modelbridge.random import RandomModelBridge
  from ax.modelbridge.registry import Cont_X_trans
  from ax.models.random.base import RandomModel
  from ax.models.random.sobol import SobolGenerator
  from ax.utils.common.testutils import TestCase
  from ax.utils.testing.core_stubs import get_small_discrete_search_space
label_desc: Use image node_id 4 for calling the RandomModelBridgeTest obj's underlying member method code with example usage: obj.test_CrossValidate(mock_init) without return types