code: def test_Transform(self) -> None:
      obsd1_0 = ObservationData(
          metric_names=["m1", "m2", "m2"],
          means=np.array([1.0, 2.0, 1.0]),
          covariance=np.array(
              [[1.0, 0.2, 0.4], [0.2, 2.0, 0.8], [0.4, 0.8, 3.0]]
          ),
      )
      obsd1_1 = ObservationData(
          metric_names=["m1", "m1", "m2", "m2"],
          means=np.array([1.0, 1.0, 2.0, 1.0]),
          covariance=np.array(
              [
                  [1.0, 0.0, 0.0, 0.0],
                  [0.0, 1.0, 0.2, 0.4],
                  [0.0, 0.2, 2.0, 0.8],
                  [0.0, 0.4, 0.8, 3.0],
              ]
          ),
      )
      obsd2_0 = ObservationData(
          metric_names=["m1", "m2"],
          means=np.array([1.0, 1.6]),
          covariance=np.array([[1.0, 0.28], [0.28, 1.584]]),
      )
      obsd2_1 = ObservationData(
          metric_names=["m1", "m2"],
          means=np.array([1.0, 1.6]),
          covariance=np.array([[0.5, 0.14], [0.14, 1.584]]),
      )
      observation_data = [obsd1_0, obsd1_1]
      t = IVW(None, [])
      observation_data2 = t._transform_observation_data(
          observation_data
      )
      observation_data2_true = [obsd2_0, obsd2_1]
      for i, obsd in enumerate(observation_data2_true):
          self.assertEqual(
              observation_data2[i].metric_names, obsd.metric_names
          )
          self.assertTrue(
              np.array_equal(observation_data2[i].means, obsd.means)
          )
          discrep = np.max(
              np.abs(observation_data2[i].covariance - obsd.covariance)
          )
          self.assertTrue(discrep < 1e-8)
  
file_path: Ax/ax/modelbridge/transforms/tests/test_ivw_transform.py
imports: import numpy
  from ax.core.observation import ObservationData
  from ax.modelbridge.transforms.ivw import IVW, ivw_metric_merge
  from ax.utils.common.testutils import TestCase
label_desc: Use image node_id 4 for calling the IVWTransformTest obj's underlying member method code with example usage: obj.test_Transform() without return types