code: def sound_norm(x):
      return x / abs(x).max() * 0.9
  
imports: import librosa
  import soundfile
  import numpy
  import scipy.io.wavfile
  import scipy.signal
  from TTS.tts.utils.data import StandardScaler
label_desc: Use image node_id 25 for calling the AudioProcessor obj's underlying member method code with example usage: obj.sound_norm(x) and returns: unknown