why doesn't misp.search_index(publish=False) return events with zero attributes?

[github-germ]

We've noticed that search_index does not include events with zero attributes in the result.

 eventList = misp.search_index(
        published = False,
        pythonify = False,
        minimal   = True)

Is there another method to retrieve those. We use these type of queries to detect opportunities of data mitigation.

Thanks.