code: def setUp(self) -> None:
      self.search_space = SearchSpace(
          parameters=[
              RangeParameter(
                  "a",
                  lower=1,
                  upper=3,
                  parameter_type=ParameterType.FLOAT,
              ),
              ChoiceParameter(
                  "b",
                  parameter_type=ParameterType.STRING,
                  values=["a", "b", "c"],
              ),
          ]
      )
      self.observation_features = [
          ObservationFeatures(parameters={"a": 2, "b": "a"}),
          ObservationFeatures(parameters={"a": 3, "b": "b"}),
          ObservationFeatures(parameters={"a": 3, "b": "c"}),
      ]
      self.signature_to_parameterization = {
          Arm(parameters=obsf.parameters).signature: obsf.parameters
          for obsf in self.observation_features
      }
      self.transformed_features = [
          ObservationFeatures(
              parameters={
                  "arms": Arm(parameters={"a": 2, "b": "a"}).signature
              }
          ),
          ObservationFeatures(
              parameters={
                  "arms": Arm(parameters={"a": 3, "b": "b"}).signature
              }
          ),
          ObservationFeatures(
              parameters={
                  "arms": Arm(parameters={"a": 3, "b": "c"}).signature
              }
          ),
      ]
      self.observations = [
          Observation(
              data=ObservationData([], np.array([]), np.empty((0, 0))),
              features=obsf,
          )
          for obsf in self.observation_features
      ]
      self.t = SearchSpaceToChoice(
          search_space=self.search_space,
          observations=self.observations,
      )
      self.t2 = SearchSpaceToChoice(
          search_space=self.search_space,
          observations=self.observations[:1],
      )
      self.t3 = SearchSpaceToChoice(
          search_space=self.search_space,
          observations=self.observations,
          config={"use_ordered": True},
      )
  
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 1 for calling the SearchSpaceToChoiceTest obj's underlying member method code with example usage: obj.setUp() without return types