For example I want to create two delivery orders from quotation that depends on express delivery or usual delivery. Every order line has checkbox that shows express or not.

The problem is in process sale order -> procurement order -> moves -> delivery order. I can't understand the structure of this process, can't find method where procurement order have been created, can't find point(points) what to inherit in my code.

I found _action_confirm method in sales/sale.py,

The description: """ Implementation of additionnal mecanism of Sales Order confirmation. This method should be extended when the confirmation should generated other documents. In this method, the SO are in 'sale' state (not yet 'done'). """

but what method should I use to create another delivery order?

Will be grateful for any help or hint.