public static function setStopWords($stop_words_path, $options = array())
    {
        $content = fopen($stop_words_path, "r");

        while (($line = fgets($content)) !== false) {
            $stop_word = strtolower(trim($line));
            if (! in_array($stop_word, self::$stop_words)) {
                array_push(self::$stop_words, $stop_word);
            }
        }
        fclose($content);
    }