def __setitem__(self, idx, value):
        return self.database.lset(self.key, idx, value)
NOT_FOUND is returned if the requested dataset_id doesn't exist.
dataset/ETHPy150Open coleifer/walrus/walrus/containers.py/List.__setitem__--crossover with--dataset/ETHPy150Open ClusterHQ/flocker/flocker/control/test/test_httpapi.py/DeleteDatasetTestsMixin.test_unknown_dataset