code: def distance_and_image_from_frac_coords(self, fcoords, jimage=None):
          
          return self.lattice.get_distance_and_image(self.frac_coords, fcoords,
                                                     jimage=jimage)
docs: Gets distance between site and a fractional coordinate assuming
          periodic boundary conditions. If the index jimage of two sites atom j
          is not specified it selects the j image nearest to the i atom and
          returns the distance and jimage indices in terms of lattice vector
          translations. If the index jimage of atom j is specified it returns the
          distance between the i atom and the specified jimage atom, the given
          jimage is also returned.
  
          Args:
              fcoords (3x1 array): fcoords to get distance from.
              jimage (3x1 array): Specific periodic image in terms of
                  lattice translations, e.g., [1,0,0] implies to take periodic
                  image that is one a-lattice vector away. If jimage is None,
                  the image that is nearest to the site is found.
  
          Returns:
              (distance, jimage): distance and periodic lattice translations
              of the other site for which the distance applies.