def save_grid_service(grid_service)
      if grid_service.save
        return grid_service
      else
        grid_service.errors.each do |key, message|
          add_error(key, :invalid, message)
        end
        return nil
      end
    end
def save_grid_service(grid_service)
      if grid_service.save
        return grid_service
      else
        grid_service.errors.each do |key, message|
          add_error(key, :invalid, message)
        end
        return nil
      end
    end
Adds errors if save fails

 @param grid_service [GridService]
 @return [GridService] nil if error