MailingList target, MailingList source, boolean sourceDominant, Map<Object, Object> context) {
        String src = source.getUnsubscribe();
        if (src != null) {
            if (sourceDominant || target.getUnsubscribe() == null) {
                target.setUnsubscribe(src);
                target.setLocation("unsubscribe", source.getLocation("unsubscribe"));
            }
        }
    }