src/Magento/Invoice/Source.php
protected function getPaymentStatusOrder()
    {
        return Number::isZero($this->source->getBaseTotalDue())
            ? Api::PaymentStatus_Paid
            : Api::PaymentStatus_Due;
    }
protected function getPaymentStatusOrder()
    {
        return Number::isZero($this->source->getBaseTotalDue())
            ? Api::PaymentStatus_Paid
            : Api::PaymentStatus_Due;
    }
protected function getPaymentStatusOrder ( ) { return Number :: isZero ( $ this -> source -> getBaseTotalDue ( ) ) ? Api :: PaymentStatus_Paid : Api :: PaymentStatus_Due ; }
Returns whether the order has been paid or not.

@return int
\Siel\Acumulus\Api::PaymentStatus_Paid or
\Siel\Acumulus\Api::PaymentStatus_Due
Returns whether the order has been paid or not .