code: def _istft(self, y):
      return librosa.istft(
          y, hop_length=self.hop_length, win_length=self.win_length
      )
  
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 20 for calling the AudioProcessor obj's underlying member method code with example usage: obj._istft(y) and returns: librosa