code: def testNormalization(self):
      result = RollOff(sampleRate=200, cutoff=0.5)([1] * 101)
      self.assertAlmostEqual(result, 50)
  
file_path: essentia/test/src/unittests/spectral/test_rolloff.py
imports: from essentia_test import *
label_desc: Use image node_id 8 for calling the TestRollOff obj's underlying member method code with example usage: obj.testNormalization() without return types