code: def test_scaler(self):
      scaler_stats_path = os.path.join(
          get_tests_input_path(), "scale_stats.npy"
      )
      conf.audio["stats_path"] = scaler_stats_path
      conf.audio["preemphasis"] = 0.0
      conf.audio["do_trim_silence"] = True
      conf.audio["signal_norm"] = True
  
      ap = AudioProcessor(**conf.audio)
      mel_mean, mel_std, linear_mean, linear_std, _ = ap.load_stats(
          scaler_stats_path
      )
      ap.setup_scaler(mel_mean, mel_std, linear_mean, linear_std)
  
      self.ap.signal_norm = False
      self.ap.preemphasis = 0.0
  
      # test scaler forward and backward transforms
      wav = self.ap.load_wav(WAV_FILE)
      mel_reference = self.ap.melspectrogram(wav)
      mel_norm = ap.melspectrogram(wav)
      mel_denorm = ap.denormalize(mel_norm)
      assert abs(mel_reference - mel_denorm).max() < 1e-4
  
file_path: TTS/tests/test_audio.py
imports: import os
  import unittest
  from tests import get_tests_input_path, get_tests_output_path, get_tests_path
  from TTS.utils.audio import AudioProcessor
  from TTS.utils.io import load_config
label_desc: Use image node_id 4 for calling the TestAudio obj's underlying member method code with example usage: obj.test_scaler() without return types