Shipment/Gateway/AbstractGateway.php
protected function hasLabelData(Shipment\ShipmentInterface $shipment)
    {
        if ($shipment->hasParcels()) {
            foreach ($shipment->getParcels() as $parcel) {
                if (!$parcel->hasLabels()) {
                    return false;
                }
            }

            return true;
        }

        return $shipment->hasLabels();
    }
protected function hasLabelData(Shipment\ShipmentInterface $shipment)
    {
        if ($shipment->hasParcels()) {
            foreach ($shipment->getParcels() as $parcel) {
                if (!$parcel->hasLabels()) {
                    return false;
                }
            }

            return true;
        }

        return $shipment->hasLabels();
    }
Returns whether the shipment (or its parcels) has label(s) data.

@param Shipment\ShipmentInterface $shipment

@return bool Whether the given shipment has label data.