PayPal\PayPalAPI\CreateBillingAgreementReq::toXMLString PHP Метод

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