private function executeSearch($query, $limit, $start, $sort = null)
    {
        $qParam = new Parameter\Query($query);
        $groupParam = new Parameter\Group();
        $startParam = new Parameter\Start($start);
        $limitParam = new Parameter\Rows($limit);
        $typeParam = new Parameter\FilterQuery('type:event OR (type:actor AND category_id:8.15.0.0.0)');

        $params = array(
            $qParam,
            $groupParam,
            $limitParam,
            $startParam,
            $typeParam,
        );

        if ($this->includePrivateItems) {
            $privateParam = new Parameter\FilterQuery('private:*');

            $params[] = $privateParam;
        }

        if ($sort) {
            $params[] = new Parameter\Parameter('sort', $sort);
        }

        $response = $this->searchAPI2->search($params);

        return $response;
    }