code: def test_fund_fre(self):
      np.testing.assert_almost_equal(
          fundamental_frequency(const0, 1), 0.0
      )
      np.testing.assert_almost_equal(
          fundamental_frequency(const1, 1), 0.0
      )
      np.testing.assert_almost_equal(
          fundamental_frequency(constNeg, Fs), 0.0
      )
      np.testing.assert_almost_equal(
          fundamental_frequency(constF, Fs), 0.0
      )
      np.testing.assert_almost_equal(
          fundamental_frequency(lin, Fs), 50.0
      )
      np.testing.assert_almost_equal(
          fundamental_frequency(lin0, Fs), 50.0, decimal=1
      )
      np.testing.assert_almost_equal(
          fundamental_frequency(wave, Fs), 5.0100200400801596, decimal=1
      )
      np.testing.assert_almost_equal(
          fundamental_frequency(offsetWave, Fs),
          5.0100200400801596,
          decimal=1,
      )
      np.testing.assert_almost_equal(
          fundamental_frequency(noiseWave, Fs),
          5.0100200400801596,
          decimal=1,
      )
  
imports: import unittest
  import numpy
  from tsfel.feature_extraction.features import *
label_desc: Use image node_id 37 for calling the TestFeatures obj's underlying member method code with example usage: obj.test_fund_fre() without return types