code: def test_TransformSearchSpaceWithFixedParam(self) -> None:
      ss2 = self.search_space.clone()
      ss2 = self.t2.transform_search_space(ss2)
      self.assertEqual(len(ss2.parameters), 1)
      expected_parameter = FixedParameter(
          name="arms",
          parameter_type=ParameterType.STRING,
          value=list(self.t2.signature_to_parameterization.keys())[0],
      )
      self.assertEqual(ss2.parameters.get("arms"), expected_parameter)
  
file_path: Ax/ax/modelbridge/transforms/tests/test_search_space_to_choice_transform.py
imports: from copy import deepcopy
  import numpy
  from ax.core.arm import Arm
  from ax.core.observation import Observation, ObservationData, ObservationFeatures
  from ax.core.parameter import ChoiceParameter, FixedParameter, ParameterType, RangeParameter
  from ax.core.search_space import SearchSpace
  from ax.exceptions.core import UnsupportedError
  from ax.modelbridge.transforms.search_space_to_choice import SearchSpaceToChoice
  from ax.utils.common.testutils import TestCase
  from ax.utils.testing.core_stubs import get_robust_search_space
label_desc: Use image node_id 3 for calling the SearchSpaceToChoiceTest obj's underlying member method code with example usage: obj.test_TransformSearchSpaceWithFixedParam() without return types