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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def upsert(self, doc, namespace, timestamp):
 """Update or insert a document into Mongo """

        database, coll = self._db_and_collection(namespace)

        meta_collection_name = self._get_meta_collection(namespace)

        self.meta_database[meta_collection_name].replace_one(
            {self.id_field: doc["_id"], "ns": namespace},
            {self.id_field: doc["_id"], "_ts": timestamp, "ns": namespace},
            upsert=True,
        )

        self.mongo[database][coll].replace_one({"_id": doc["_id"]}, doc, upsert=True)