protected function checkProperties(): void
    {
        foreach (get_object_vars($this) as $property => $value) {
            if ($property !== "dueDate" && strpos($value, "*") !== false) {
                throw new QrPaymentException("Error: properties cannot contain asterisk (*). Property $property contains it.", QrPaymentException::ERR_ASTERISK);
            }
        }
    }