}
        return model;
    }

    private <T> List<T> map(List<T> resources, Function<T, T> mapper) {
        List<T> newResources = null;
        if (resources != null) {
            for (int i = 0; i < resources.size(); i++) {
                T resource = resources.get(i);
                T newResource = mapper.apply(resource);
                if (newResource != null) {
                    if (newResources == null) {