code: def test_kurtosis(self):
      self.assertTrue(np.isnan(kurtosis(const0)))
      self.assertTrue(np.isnan(kurtosis(const1)))
      self.assertTrue(np.isnan(kurtosis(constNeg)))
      self.assertTrue(np.isnan(kurtosis(constF)))
      np.testing.assert_almost_equal(
          kurtosis(lin), -1.206015037593985, decimal=2
      )
      np.testing.assert_almost_equal(
          kurtosis(lin0), -1.2060150375939847, decimal=2
      )
      np.testing.assert_almost_equal(
          kurtosis(wave), -1.501494077162359, decimal=2
      )
      np.testing.assert_almost_equal(
          kurtosis(offsetWave), -1.5014940771623597, decimal=2
      )
      np.testing.assert_almost_equal(
          kurtosis(noiseWave), -1.4606204906023366, decimal=2
      )
  
imports: import unittest
  import numpy
  from tsfel.feature_extraction.features import *
label_desc: Use image node_id 3 for calling the TestFeatures obj's underlying member method code with example usage: obj.test_kurtosis() without return types