code: def test_abs_energy(self):
      np.testing.assert_almost_equal(abs_energy(const0), 0.0)
      np.testing.assert_almost_equal(abs_energy(const1), 20.0)
      np.testing.assert_almost_equal(abs_energy(constNeg), 20.0)
      np.testing.assert_almost_equal(abs_energy(constF), 125.0)
      np.testing.assert_almost_equal(abs_energy(lin), 2470)
      np.testing.assert_almost_equal(
          abs_energy(lin0), 736.8421052631579
      )
      np.testing.assert_almost_equal(abs_energy(wave), 500.0)
      np.testing.assert_almost_equal(abs_energy(offsetWave), 4500.0)
      np.testing.assert_almost_equal(
          abs_energy(noiseWave), 508.11883669335725
      )
  
imports: import unittest
  import numpy
  from tsfel.feature_extraction.features import *
label_desc: Use image node_id 30 for calling the TestFeatures obj's underlying member method code with example usage: obj.test_abs_energy() without return types