private function parseDate($rawDate)
    {
        foreach (['Y-m-d', 'Y-m', 'Y'] as $dateFormat) {
            $publishedDate = DateTime::createFromFormat($dateFormat.'|', $rawDate);
            if ($publishedDate !== false) {
                break;
            }
        }

        if ($publishedDate === false) {
            $publishedDate = null;
        }

        return [$publishedDate, $dateFormat];
    }