code: def upsert(self, doc, namespace, timestamp):
          
          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)
docs: Update or insert a document into Mongo