code: def normalize(audio, target_level=-25):
      """Normalize the signal to the target level"""
      rms = (audio**2).mean() ** 0.5
      scalar = 10 ** (target_level / 20) / (rms + EPS)
      audio = audio * scalar
      return audio
  
file_path: speechbrain/recipes/DNS/noisyspeech_synthesizer/audiolib.py
imports: import os
  import numpy
  import soundfile
  import subprocess
  import glob
  import librosa
label_desc: Use image node_id 2 for calling a global function with example usage: normalize(audio, target_level) and returns: audio