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