code: def testEmptyOnsets(self):
      signal = [0.1, 0.2, 0.3]
      audio = AudioOnsetsMarker(sampleRate=44100, onsets=[])(signal)
      MonoWriter(filename=file)(audio)
      mix = MonoLoader(filename=file, downmix="mix", sampleRate=44100)()
      os.remove(file)
      expected = [0.5 * val for val in signal]
      self.assertAlmostEqualVector(mix, expected, 1e-3)
  
file_path: essentia/test/src/unittests/io/test_audioonsetsmarker.py
imports: from essentia_test import *
  from numpy import pi, sin
  import os
  import essentia.streaming
label_desc: Use image node_id 3 for calling the TestAudioOnsetsMarker obj's underlying member method code with example usage: obj.testEmptyOnsets() without return types