delete empty sub-dicts
delete empty sub-dicts

arpitgoyaiitkgp/django-mongoengine,seraphlnWu/django-mongoengine,vetional/django-mongoengine,arpitgoyaiitkgp/django-mongoengine,vetional/django-mongoengine,vetional/django-mongoengine,seraphlnWu/django-mongoengine,seraphlnWu/django-mongoengine,arpitgoyaiitkgp/django-mongoengine