gistfile1.txt

    def get_sale_address(self, cr, uid, partner_id, type, context=None):
        base_search = ('parent_id', '=', partner_id)
        if type == 'invoice':
            preferred = 'is_default_billing'
        elif type == 'delivery':
            preferred = 'is_default_shipping'
        else:
            preferred = False

        if preferred:
            preferred_ids = self.search(cr, uid, [(preferred, '=', True), ('type', '=', type), base_search])
            if preferred_ids:
                return preferred_ids[0]

        address_ids = self.search(cr, uid, [('type', '=', type), base_search])
        if address_ids:
            return address_ids[0]

        contact_ids = self.search(cr, uid, [('type', '=', 'contact'), base_search])
        if not contact_ids:
            return partner_id

        return contact_ids[0]