/**
* @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;
}
