PayPal\PayPalAPI\BillUserReq::toXMLString PHP 메소드

    public function toXMLString()
    {
        $str = '';
        $str .= '<ns:BillUserReq>';
        if ($this->BillUserRequest != null) {
            $str .= '<ns:BillUserRequest>';
            $str .= $this->BillUserRequest->toXMLString();
            $str .= '</ns:BillUserRequest>';
        }
        $str .= '</ns:BillUserReq>';
        return $str;
    }