public static function createMultiple(
        $number,
        $length = 10,
        $type = 'pronounceable',
        $chars = ''
    ) {
        $passwords = array();

        while ($number > 0) {
            while (true) {
                $password = self::create($length, $type, $chars);
                if (!in_array($password, $passwords)) {
                    $passwords[] = $password;
                    break;
                }
            }
            $number--;
        }
        return $passwords;
    }