VladFastPersist

    def save(self):
        # Implemented in a batch processing fashion
        visited_fps = set()  # the fingerprints that the current document has
        doc = {
            '_id': self.url,
            'fingerprints': self.fingerprints
        }
        db.news_collection.insert_one(doc)

        for fp in self.fingerprints:
            if fp not in visited_fps:
                visited_fps.add(fp)
        existing_fps = set(db.hashes_collection.find({}, {"_id": 1}).distinct('_id')) # the already existing fps in the collection
        need_to_update_fps = visited_fps & existing_fps  # the already existing fp_s
        need_to_insert_fps = visited_fps - need_to_update_fps  # the fp_s that need to be inserted
        # Update matching documents in hashes_collection collection

        filter_condition = {"_id": {"$in": list(need_to_update_fps)}}
        update_query = {"$addToSet": {"urls": self.url}}
        db.hashes_collection.update_many(filter_condition, update_query)
        to_insert = []
        for i in need_to_insert_fps:
            to_insert.append({"_id": i, "urls": [self.url]})
        if len(to_insert) != 0:
            db.hashes_collection.insert_many(to_insert)