code: def test_Init(self) -> None:
      with self.assertRaises(DataRequiredError):
          PercentileY(search_space=None, observations=[])
  
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 2 for calling the PercentileYTransformTest obj's underlying member method code with example usage: obj.test_Init() without return types