Aggregation In Flask-mongoengine

I'm just staring out with MongoDB and I'm staring an application with flask-mongoengine and I want to aggregate a few documents. I'm using flask-mongoengine and when trying class M

Solution 1:

Starting with mongoengine v0.9 (which is currently in development), you will be able to use aggregate(), like you suggested: http://docs.mongoengine.org/apireference.html#mongoengine.queryset.QuerySet.aggregate

Until then, you need to rely on pymongo: Flask-MongoEngine & PyMongo Aggregation Query