/** * @param string $shipmentExternalId * @param string $rateExternalId * @return ShipmentTracker */ public function buy($shipmentExternalId, $rateExternalId) { $dummyData = new DummyData(); $shipmentTracker = $dummyData->getShipmentTracker(); $shipmentTracker->getShipmentLabel()->setExternalId($shipmentExternalId); $shipmentTracker->getShipmentRate()->setExternalId($rateExternalId); return $shipmentTracker; }