def arrange_single_notification_index(loading_index_method, options = {})
        as_latest_group_member = options[:as_latest_group_member] || false
        as_latest_group_member ?
          loading_index_method.call(options).map{ |n| n.latest_group_member } :
          loading_index_method.call(options).to_a
      end
def arrange_single_notification_index(loading_index_method, options = {})
        as_latest_group_member = options[:as_latest_group_member] || false
        as_latest_group_member ?
          loading_index_method.call(options).map{ |n| n.latest_group_member } :
          loading_index_method.call(options).to_a
      end
Gets arranged single notification index of the target.
 @api private

 @param [Method] loading_index_method Method to load index
 @param [Hash] options Options for notification index
 @option options [Integer]    :limit                  (nil)   Limit to query for notifications
 @option options [Boolean]    :reverse                (false) If notification index will be ordered as earliest first
 @option options [Boolean]    :with_group_members     (false) If notification index will include group members
 @option options [Boolean]    :as_latest_group_member (false) If grouped notification will be shown as the latest group member (default is shown as the earliest member)
 @option options [String]     :filtered_by_type       (nil)   Notifiable type for filter
 @option options [Object]     :filtered_by_group      (nil)   Group instance for filter
 @option options [String]     :filtered_by_group_type (nil)   Group type for filter, valid with :filtered_by_group_id
 @option options [String]     :filtered_by_group_id   (nil)   Group instance id for filter, valid with :filtered_by_group_type
 @option options [String]     :filtered_by_key        (nil)   Key of the notification for filter
 @option options [Array|Hash] :custom_filter          (nil)   Custom notification filter (e.g. ["created_at >= ?", time.hour.ago])
 @return [Array<Notificaion>] Notification index of the target