code: def testRegression(self):
      # this algorithm has a standard mode implementation which has been
      # tested thru the unitests in python. Therefore it's only tested that
      # for a certain input standard == streaming
      envelope = list(range(22050))
      envelope.reverse()
      envelope = list(range(22050)) + envelope
  
      # Calculate standard result
      stdResult = FlatnessSFX()(envelope)
  
      # Calculate streaming result
      p = Pool()
      input = VectorInput(envelope)
      accu = RealAccumulator()
      strFlatnessSfx = sFlatnessSFX()
  
      input.data >> accu.data
      accu.array >> strFlatnessSfx.envelope
      strFlatnessSfx.flatness >> (p, "lowlevel.flatness")
  
      run(input)
      strResult = p["lowlevel.flatness"]
  
      # compare results
      self.assertEqual(len(strResult), 1)
      self.assertAlmostEqual(strResult[0], stdResult, 5e-7)
  
imports: from essentia_test import *
  from essentia.streaming import FlatnessSFX
label_desc: Use image node_id 1 for calling the TestFlatnessSfx_Streaming obj's underlying member method code with example usage: obj.testRegression() without return types