public function withScope($scope)
    {
        if ($scope == Grid\Exporter::SCOPE_ALL) {
            return $this;
        }

        list($scope, $args) = explode(':', $scope);

        if ($scope == Grid\Exporter::SCOPE_CURRENT_PAGE) {
            $this->grid->model()->usePaginate(true);
        }

        if ($scope == Grid\Exporter::SCOPE_SELECTED_ROWS) {
            $selected = explode(',', $args);
            $this->grid->model()->whereIn($this->grid->getKeyName(), $selected);
        }

        return $this;
    }