def aggregate(self):
return Aggregation(self)
def aggregate(self, group_by, project=None, unwind=None, callback=None, alias=None):
coll = self.coll(alias)
agg = Aggregation(self, group=group_by, project=project, unwind=unwind)
coll.aggregate(agg.to_query(), callback=agg.handle_aggregation(callback))