code: def testEmpty(self):
      audio = AudioOnsetsMarker(sampleRate=44100, onsets=[1, 2, 3])([])
      MonoWriter(filename=file)(audio)
      self.assertTrue(not os.path.exists(file))
  
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 2 for calling the TestAudioOnsetsMarker obj's underlying member method code with example usage: obj.testEmpty() without return types