source/Application/Model/Basket.php
public function getPaymentId()
    {
        if (!$this->_sPaymentId) {
            $this->_sPaymentId = \OxidEsales\Eshop\Core\Registry::getSession()->getVariable('paymentid');
        }

        return $this->_sPaymentId;
    }
public function getPaymentId()
    {
        if (!$this->_sPaymentId) {
            $this->_sPaymentId = \OxidEsales\Eshop\Core\Registry::getSession()->getVariable('paymentid');
        }

        return $this->_sPaymentId;
    }
public function getPaymentId ( ) { if ( ! $ this -> _sPaymentId ) { $ this -> _sPaymentId = \ OxidEsales \ Eshop \ Core \ Registry :: getSession ( ) -> getVariable ( 'paymentid' ) ; } return $ this -> _sPaymentId ; }
Get basket payment, if payment id is not set, try to get it from session

@return string
Get basket payment if payment id is not set try to get it from session