code: def fwhm2sigma(fwhm):
      
      fwhm = np.asarray(fwhm)
      return fwhm / np.sqrt(8 * np.log(2))
docs: Convert a FWHM value to sigma in a Gaussian kernel.
  
      Parameters
      ----------
      fwhm: float or numpy.array
         fwhm value or values
  
      Returns
      -------
      fwhm: float or numpy.array
         sigma values