I want that when you change the suplier in the Purchas Order, automatically change the description of the products in the order lines, meeting the code and the name of that supplier if it is specified in  the product. The problem is that this code changes everything to the first value. What can I do to go line by line checking the product name and not putting all time the same

@api.onchange('partner_id')
def _onchange_partner_id(self):
    for order in self:
        product_lang = self.product_id.with_context(
            lang=self.partner_id.lang,
            partner_id=self.partner_id.id,
        )
        self.name = product_lang.display_name
        if product_lang.description_purchase:
            self.name += '\n' + product_lang.description_purchase
        for line in order.order_line:
            line.name = self.name