When shipping internationall using PostNord in this case, but typically with all carriers importing into Norway, you may be asked to specify a declaration_sequence when booking shipments via the API. The declaration_sequence is used for customs declarations on international shipments as part of Norway's TVINN system.
It identifies the order of each item in a shipment when multiple items are declared separately for customs purposes.
Example Itemised customs declarations usage
If a parcel contains multiple products, each item must be declared individually. declaration_sequence assigns a number to each item, such as 1, 2, or 3.
The sequence number links each item to its declared value, weight, and HS code.