public function getMonthSummary($parentObject, $options = [])
    {
        $limit = isset($options['limit_months']) ? $options['limit_months'] : 5;
        $query = $this->getBaseStatsQuery($parentObject);
        $query->select(['DATE_FORMAT(log_date, \'%Y-%m\') as month', 'SUM(`hours`) as sum']);
        $query->groupBy(['YEAR(log_date)', 'MONTH(log_date)']);
        $query->addOrderBy(['log_date' => SORT_DESC]);
        $query->limit($limit);
        $c = [];
        foreach ($query->each() as $row) {
            $c[$row['month']] = [
                'sum' => $row['sum'],
            ];
        }

        return $c;
    }