code: def test_melspectrogram_load_save(self):
      waveform = self.waveform.float()
      mel_spectrogram_transform = transforms.MelSpectrogram()
      mel_spectrogram_transform(waveform)
  
      mel_spectrogram_transform_copy = transforms.MelSpectrogram()
      mel_spectrogram_transform_copy.load_state_dict(
          mel_spectrogram_transform.state_dict()
      )
  
      window = mel_spectrogram_transform.spectrogram.window
      window_copy = mel_spectrogram_transform_copy.spectrogram.window
  
      fb = mel_spectrogram_transform.mel_scale.fb
      fb_copy = mel_spectrogram_transform_copy.mel_scale.fb
  
      self.assertEqual(window, window_copy)
      # the default for n_fft = 400 and n_mels = 128
      self.assertEqual(fb_copy.size(), (201, 128))
      self.assertEqual(fb, fb_copy)
  
imports: import math
  import torch
  import torchaudio
  import torchaudio.functional
  import torchaudio.transforms
  from torchaudio_unittest import common_utils
label_desc: Use image node_id 5 for calling the Tester obj's underlying member method code with example usage: obj.test_melspectrogram_load_save() without return types