code: def _get_azimuth_elev(self, miller_index):
          
          if miller_index == (0, 0, 1) or miller_index == (0, 0, 0, 1):
              return 0, 90
          else:
              cart = self.lattice.get_cartesian_coords(miller_index)
              azim = get_angle([cart[0], cart[1], 0], (1, 0, 0))
              v = [cart[0], cart[1], 0]
              elev = get_angle(cart, v)
              return azim, elev
docs: Args:
              miller_index: viewing direction
  
          Returns:
              azim, elev for plotting