public function getUsedLocales()
    {
        $queryBuilder = $this->createQueryBuilder('blog')
            ->select('DISTINCT(b_translation.locale) AS locale')
            ->join('blog.translations', 'b_translation');

        $locales = [];
        foreach ($queryBuilder->getQuery()->getResult() as $locale) {
            $locales[] = $locale['locale'];
        }

        return $locales;
    }