crodas\TextRank\Stopword::filter_keywords PHP Method

    public function filter_keywords(array $keywords)
    {
        $keywords = parent::filter_keywords($keywords);
        $tagger = __NAMESPACE__ . '\\POS\\' . ucfirst($this->lang) . '\\Tagger';
        if (class_exists($tagger)) {
            $keywords = $tagger::get($keywords);
        }
        $keywords = array_filter($keywords, function ($word) {
            $word = mb_strtolower($word);
            return empty($this->stopword[$word]);
        });
        return $keywords;
    }