I also need this....Any luck?

Edit:

I used this answer:

https://www.odoo.com/forum/help-1/odoov13-how-to-assign-a-delivery-carrier-object-to-a-sale-order-object-using-orm-179786#

in combination with ChatGPT and have this so far and it seems OK:

```

    # ID of the desired shipping method

    shipping_method_id = 70

    # Check if a delivery line with the specified shipping method exists

    delivery_line_exists = any(

        line.product_id.id == env['delivery.carrier'].browse(shipping_method_id).product_id.id

        for line in record.order_line if line.is_delivery

    )

    if not delivery_line_exists:

        # Fetch the delivery carrier by its ID

        delivery_carrier = env['delivery.carrier'].browse(shipping_method_id)

        if delivery_carrier:

            # Use the set_delivery_line method to add or update the delivery line

            record.set_delivery_line(delivery_carrier, delivery_carrier.rate_shipment(record)['price']) 
```