code: def test_spectral_slope(self):
      np.testing.assert_almost_equal(spectral_slope(const0, Fs), 0.0)
      np.testing.assert_almost_equal(
          spectral_slope(const1, Fs), -0.0009090909090909091
      )
      np.testing.assert_almost_equal(
          spectral_slope(constNeg, Fs), -0.0009090909090909091
      )
      np.testing.assert_almost_equal(
          spectral_slope(constF, Fs), -0.0009090909090909091
      )
      np.testing.assert_almost_equal(
          spectral_slope(lin, Fs), -0.0005574279006023302
      )
      np.testing.assert_almost_equal(
          spectral_slope(lin0, Fs), -0.00023672490168659717, decimal=1
      )
      np.testing.assert_almost_equal(
          spectral_slope(wave, Fs), -2.3425149700598465e-05, decimal=5
      )
      np.testing.assert_almost_equal(
          spectral_slope(offsetWave, Fs),
          -2.380838323353288e-05,
          decimal=5,
      )
      np.testing.assert_almost_equal(
          spectral_slope(noiseWave, Fs),
          -6.586047565550932e-06,
          decimal=5,
      )
  
imports: import unittest
  import numpy
  from tsfel.feature_extraction.features import *
label_desc: Use image node_id 44 for calling the TestFeatures obj's underlying member method code with example usage: obj.test_spectral_slope() without return types