-Returns C<undef> on failure. Otherwise the return value depends on the
-context. In list context the new delivery order and a shipto instance
-will be returned. In scalar instance only the delivery order instance
-is returned.
-
-Custom shipto addresses (the ones specific to the sales/purchase
-record and not to the customer/vendor) are only linked from C<shipto>
-to C<delivery_orders>. Meaning C<delivery_orders.shipto_id> will not
-be filled in that case. That's why a separate shipto object is created
-and returned.