public function getCachingDependency($parentObject)
    {
        //$primaryModel = $this->primaryModel;
        //$alias = $primaryModel::tableName();
        $baseQuery = $this->getBaseStatsQuery($parentObject);
        $baseQuery->select(['innerQuery.modified']);
        $baseQuery->addOrderBy(['innerQuery.modified' => SORT_DESC]);
        $baseQuery->limit(1);
        $cacheSql = $baseQuery->createCommand()->rawSql;

        return new DbDependency(['sql' => $cacheSql]);
    }