docs: def plotfft(s, fmax, doplot=False):
      """
      -----
      Brief
      -----
      This functions computes the Fast Fourier Transform of a signal, returning the frequency and magnitude values.
  
      -----------
      Description
      -----------
      Fast Fourier Transform (FFT) is a method to computationally calculate the Fourier Transform of discrete finite
      signals. This transform converts the time domain signal into a frequency domain signal by abdicating the temporal
      dimension.
  
      This function computes the FFT of the input signal and returns the frequency and respective amplitude values.
  
      ----------
      Parameters
      ----------
      s: array-like
        the input signal.
      fmax: int
        the sampling frequency.
      doplot: boolean
        a variable to indicate whether the plot is done or not.
  
      Returns
      -------
      f: array-like
        the frequency values (xx axis)
      fs: array-like
        the amplitude of the frequency values (yy axis)
      """
  
      fs = abs(numpy.fft.fft(s))
      f = numpy.linspace(0, fmax / 2, len(s) / 2)
      if doplot:
          plot(list(f[1:int(len(s) / 2)]), list(fs[1:int(len(s) / 2)]))
      return f[1:int(len(s) / 2)].copy(), fs[1:int(len(s) / 2)].copy()