code: def test_polynomial_expansion(self):
      algorithm = harmonica.Harmonica(
          test_utils.create_spec(phoenix_spec_pb2.PhoenixSpec.DNN)
      )
      self.assertAllEqual(
          [[1, 0, 1, 0], [1, 0.5, 1, 0.5]],
          algorithm.get_polynomial_expansion(
              np.array([[0, 1], [0.5, 1]]), 3
          ),
      )
  
file_path: model_search/model_search/search/harmonica_test.py
imports: from absl.testing import parameterized
  import mock
  from model_search import hparam
  from model_search.metadata import trial
  from model_search.proto import phoenix_spec_pb2
  from model_search.search import harmonica
  from model_search.search import test_utils
  import numpy
  import tensorflow.compat.v2
label_desc: Use image node_id 1 for calling the HarmonicaTest obj's underlying member method code with example usage: obj.test_polynomial_expansion() without return types