public static <T> UnboundListFlag<T> defineListFlag(String flagId, List<T> defaultValue, Class<T> elementClass,
                                                        List<String> owners, String createdAt, String expiresAt,
                                                        String description, String modificationEffect,
                                                        Predicate<List<T>> validator, Dimension... dimensions) {
        return define((fid, dval, fvec) -> new UnboundListFlag<>(fid, dval, elementClass, fvec, validator),
                flagId, defaultValue, owners, createdAt, expiresAt, description, modificationEffect, dimensions);
    }
WARNING: public for testing: All flags should be defined in {@link Flags}.
flags/src/main/java/com/yahoo/vespa/flags/Flags.java