app/code/community/Adyen/Payment/Helper/Payment.php
public function isOpenInvoiceMethod($method)
    {
        $openinvoiceType = $this->getConfigData('openinvoicetypes', Adyen_Payment_Model_Adyen_Openinvoice::METHODCODE);

        if ($method == Adyen_Payment_Model_Adyen_Openinvoice::METHODCODE && $openinvoiceType == self::AFTERPAY_DEFAULT) {
            return true;
        }

        return false;
    }
public function isOpenInvoiceMethod($method)
    {
        $openinvoiceType = $this->getConfigData('openinvoicetypes', Adyen_Payment_Model_Adyen_Openinvoice::METHODCODE);

        if ($method == Adyen_Payment_Model_Adyen_Openinvoice::METHODCODE && $openinvoiceType == self::AFTERPAY_DEFAULT) {
            return true;
        }

        return false;
    }
public function isOpenInvoiceMethod ( $ method ) { $ openinvoiceType = $ this -> getConfigData ( 'openinvoicetypes' , Adyen_Payment_Model_Adyen_Openinvoice :: METHODCODE ) ; if ( $ method == Adyen_Payment_Model_Adyen_Openinvoice :: METHODCODE && $ openinvoiceType == self :: AFTERPAY_DEFAULT ) { return true ; } return false ; }
Check if the payment method is openinvoice and the payment method type is afterpay_default

@param $method
@return bool
Check if the payment method is openinvoice and the payment method type is afterpay_default