code: def complex_cepstrum(x, n=None, axis=-1):
      r"""
      Calculates the complex cepstrum of a real valued input sequence x
      where the cepstrum is defined as the inverse Fourier transform
      of the log magnitude DFT (spectrum) of a signal. It's primarily
      used for source/speaker separation in speech signal processing.
  
      The input is altered to have zero-phase at pi radians (180 degrees)
      Parameters
      ----------
      x : ndarray
          Input sequence, if x is a matrix, return cepstrum in direction of axis
      n : int
         Size of Fourier Transform; If none, will use length of input array
      axis: int
          Direction for cepstrum calculation
      Returns
      -------
      ceps : ndarray
          Complex cepstrum result
      """
      x = cp.asarray(x)
      spectrum = cp.fft.fft(x, n=n, axis=axis)
      unwrapped = cp.unwrap(cp.angle(spectrum))
      log_spectrum, ndelay = _complex_cepstrum_kernel(
          spectrum, unwrapped
      )
      ceps = cp.fft.ifft(log_spectrum, n=n, axis=axis).real
  
      return ceps, ndelay
  
imports: import cupy
label_desc: Use image node_id 2 for calling a global function with example usage: complex_cepstrum(x, n, axis) and returns: ceps,  ndelay