code: def _griffin_lim(self, S):
      angles = np.exp(2j * np.pi * np.random.rand(*S.shape))
      S_complex = np.abs(S).astype(np.complex)
      y = self._istft(S_complex * angles)
      for _ in range(self.griffin_lim_iters):
          angles = np.exp(1j * np.angle(self._stft(y)))
          y = self._istft(S_complex * angles)
      return y
  
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 21 for calling the AudioProcessor obj's underlying member method code with example usage: obj._griffin_lim(S) and returns: y