I'm trying to print an invoice with shipping address and invoicing address in Odoo. For delivery slip, I'm able to get a customer reference from the sales order using 'o.sale_id.client_order_ref'. It gives me an error when I tried 'o.sale_id.partner_shipping_id'.
I think this is because invoice needs sale_id with many2one relation to sale.order. Is there another way instead of using sale_id to get the shipping address?