@Override
    protected void mergeModel_Contributors(
            Model target, Model source, boolean sourceDominant, Map<Object, Object> context) {
        if (target.getContributors().isEmpty()) {
            target.setContributors(new ArrayList<>(source.getContributors()));
        }
    }

    @Override
    protected void mergeModel_MailingLists(

                }
                for (Developer developer : model.getDevelopers()) {
                    visit(developer);
                }
                for (Contributor contributor : model.getContributors()) {
                    visit(contributor);
                }
                for (MailingList mailingList : model.getMailingLists()) {
                    visit(mailingList);
                }