Topi shipment API
#### Assets without serial numbers Some assets might not have a serial number (e.g. accessories). In order to send them with the shipment, explicitly pass an empty string `""` as the `serial_number` for this asset. > Note, that every asset, that has a **rent option**, requires a serial number even if it has been directly purchased. The request will fail with an according message if such a serial number is missing. > Also note, that every item of an order has to be shipped for the order to be completed. This can be done in multiple shipments.