docs: def return_single_labels(self, object_id):
          """
          Returns all labels for an object specified by the object_id
  
          Parameters
          ----------
          object_id : int, id of object in database
  
          Returns
          -------
          result : list of labels
          """
          engine = create_engine('sqlite:////' + self.dbpath)
          trainset.Base.metadata.create_all(engine)
          session_cl = sessionmaker(bind=engine)
          session = session_cl()
          tmp_object = session.query(trainset.TrainSet).get(object_id)
          return tmp_object.labels