code: def setUp(self) -> None:
      self.obsd1 = ObservationData(
          metric_names=["m1", "m2"],
          means=np.array([0.0, 0.0]),
          covariance=np.array([[1.0, 0.0], [0.0, 1.0]]),
      )
      self.obsd2 = ObservationData(
          metric_names=["m1", "m2"],
          means=np.array([1.0, 5.0]),
          covariance=np.array([[1.0, 0.0], [0.0, 1.0]]),
      )
      self.obsd3 = ObservationData(
          metric_names=["m1", "m2"],
          means=np.array([2.0, 25.0]),
          covariance=np.array([[1.0, 0.0], [0.0, 1.0]]),
      )
      self.obsd4 = ObservationData(
          metric_names=["m1", "m2"],
          means=np.array([3.0, 125.0]),
          covariance=np.array([[1.0, 0.0], [0.0, 1.0]]),
      )
      self.obsd_mid = ObservationData(
          metric_names=["m1", "m2"],
          means=np.array([1.5, 50.0]),
          covariance=np.array([[1.0, 0.0], [0.0, 1.0]]),
      )
      self.obsd_extreme = ObservationData(
          metric_names=["m1", "m2"],
          means=np.array([-1.0, 126.0]),
          covariance=np.array([[1.0, 0.0], [0.0, 1.0]]),
      )
  
      self.observations = [
          Observation(
              features=ObservationFeatures({}), data=deepcopy(obsd)
          )
          for obsd in [self.obsd1, self.obsd2, self.obsd3, self.obsd4]
      ]
      self.t = PercentileY(
          search_space=None,
          observations=self.observations,
      )
      self.t_with_winsorization = PercentileY(
          search_space=None,
          observations=self.observations,
          config={"winsorize": True},
      )
  
file_path: Ax/ax/modelbridge/transforms/tests/test_percentile_y_transform.py
imports: from copy import deepcopy
  import numpy
  from ax.core.observation import Observation, ObservationData, ObservationFeatures
  from ax.exceptions.core import DataRequiredError
  from ax.modelbridge.transforms.percentile_y import PercentileY
  from ax.utils.common.testutils import TestCase
label_desc: Use image node_id 1 for calling the PercentileYTransformTest obj's underlying member method code with example usage: obj.setUp() without return types