code: def set_grid_data(self):
          
          if self._grid_data_is_set:
              return
          self._set_mult_grid_attr()
          if not np.any(getattr(self, 'sfc_area', None)):
              try:
                  sfc_area = _grid_sfc_area(self.lon, self.lat, self.lon_bounds,
                                            self.lat_bounds)
              except AttributeError:
                  sfc_area = _grid_sfc_area(self.lon, self.lat)
              self.sfc_area = sfc_area
          try:
              self.levs_thick = utils.vertcoord.level_thickness(self.level)
          except AttributeError:
              self.level = None
              self.levs_thick = None
          self._grid_data_is_set = True
docs: Populate the attrs that hold grid data.