code: def test_start_stop(self):
      # test wave loader
      signal, sample_rate = load_wave_file(
          sample_file, start=1.0 / 44100, stop=5.0 / 44100
      )
      self.assertTrue(np.allclose(signal, [-2510, -2484, -2678, -2833]))
      self.assertTrue(len(signal) == 4)
      self.assertTrue(sample_rate == 44100)
  
imports: from __future__ import absolute_import, division, print_function
  import io
  import unittest
  from os.path import join
  from madmom.io.audio import *
  from .None import AUDIO_PATH, DATA_PATH
label_desc: Use image node_id 4 for calling the TestLoadWaveFileFunction obj's underlying member method code with example usage: obj.test_start_stop() without return types