code: def testRegression(self):
      filename = join(
          testdata.audio_dir, "recorded", "mozart_c_major_30sec.wav"
      )
      audio = MonoLoader(
          filename=filename, downmix="left", sampleRate=44100
      )()
  
      fc = FrameCutter(frameSize=4096, hopSize=512)
      windower = Windowing(type="blackmanharris62")
      specAlg = Spectrum(size=4096)
      fluxAlg = Flux()
  
      # Calculate the average flux over all frames of audio
      frame = fc(audio)
      fluxSum = 0
      count = 0
      while len(frame) != 0:
          spectrum = specAlg(windower(frame))
          fluxSum += fluxAlg(spectrum)
  
          count += 1
          frame = fc(audio)
  
      fluxAvg = float(fluxSum) / float(count)
      self.assertAlmostEqual(fluxAvg, 0.0640958007244, 5e-5)
  
file_path: essentia/test/src/unittests/spectral/test_flux.py
imports: from essentia_test import *
label_desc: Use image node_id 9 for calling the TestFlux obj's underlying member method code with example usage: obj.testRegression() without return types