Does MongoDB's $in clause guarantee order

Question

When using MongoDB\'s $in clause, does the order of the returned documents always correspond to the order of the array argument?

Answer 1

I know this question is related to Mongoose JS framework, but the duplicated one is generic, so I hope posting a Python (PyMongo) solution is fine here.

things = list(db.things.find({'_id': {'$in': id_array}}))
things.sort(key=lambda thing: id_array.index(thing['_id']))
# things are now sorted according to id_array order