public final function getResultsIds(bool $merge = true): array
    {
        $return = [];
        if (!empty($this->results)) {
            if ($merge) {
                foreach ($this->results as $result) {
                    $return = array_merge($return, $result->getIds());
                }
            } else {
                foreach ($this->results as $result) {
                    $return[] = $result->getIds();
                }
            }
        }

        return $return;
    }