class Rights {

    public static Rights fromACL(MailboxACL acl) {
        return acl.getEntries()
            .entrySet()
            .stream()
            .filter(entry -> isSupported(entry.getKey()))
            .map(Rights::toRightsBuilder)
            .reduce(builder(), Builder::combine)
            .build();
    }

    @JsonCreator public  Rights(Map<Username, List<Right>> rights);
    private  Rights(Multimap<Username, Right> rights);

}