def load_index
        case @index_options[:filter]
        when :configured, 'configured'
          @subscriptions = @target.subscription_index(@index_options.merge(with_target: true))
          @notification_keys = nil
        when :unconfigured, 'unconfigured'
          @subscriptions = nil
          @notification_keys = @target.notification_keys(@index_options.merge(filter: :unconfigured))
        else
          @subscriptions = @target.subscription_index(@index_options.merge(with_target: true))
          @notification_keys = @target.notification_keys(@index_options.merge(filter: :unconfigured))
        end
      end
def load_index
        case @index_options[:filter]
        when :configured, 'configured'
          @subscriptions = @target.subscription_index(@index_options.merge(with_target: true))
          @notification_keys = nil
        when :unconfigured, 'unconfigured'
          @subscriptions = nil
          @notification_keys = @target.notification_keys(@index_options.merge(filter: :unconfigured))
        else
          @subscriptions = @target.subscription_index(@index_options.merge(with_target: true))
          @notification_keys = @target.notification_keys(@index_options.merge(filter: :unconfigured))
        end
      end
Loads subscription index with request parameters.
 @api protected
 @return [Array] Array of subscription index