public static function checkBIC($bic, array $options = null)
    {
        $bic = preg_replace('/\s+/u', '' , $bic );   // remove whitespaces

        if(!empty($options['forceLongBic']) && strlen($bic) === 8)
            $bic .= empty($options['forceLongBicStr']) ? 'XXX' : $options['forceLongBicStr'];

        if(empty($bic) && !empty($options['allowEmptyBic']))
            return '';

        $bic = strtoupper($bic);                    // use only capital letters

        if(preg_match('/^' . self::PATTERN_BIC . '$/', $bic))
            return $bic;
        else
            return false;
    }