code: def testUnitVarianceScale_UniformValues(self):
      arr = np.array([1.0, 1.0, np.nan])
      expected = np.array([0.0, 0.0, np.nan])
      actual = mutual_information_util._unit_variance_scale(arr)
      np.testing.assert_equal(
          actual[np.isnan(actual)], expected[np.isnan(expected)]
      )
      self.assertTrue(
          np.allclose(
              expected[~np.isnan(expected)],
              actual[~np.isnan(actual)],
              atol=1e-5,
          )
      )
  
imports: from absl.testing import absltest
  from absl.testing import parameterized
  import numpy
  from tensorflow_data_validation.utils import mutual_information_util
label_desc: Use image node_id 19 for calling the RanklabMutualInformationTest obj's underlying member method code with example usage: obj.testUnitVarianceScale_UniformValues() without return types