# old config e.g. named "username--dataset_name"
                    legacy_config_name = next(iter(legacy_dataset_infos))
                    legacy_dataset_infos["default"] = legacy_dataset_infos.pop(legacy_config_name)
            legacy_dataset_infos.update(dataset_infos)
            dataset_infos = legacy_dataset_infos
        except FileNotFoundError:
            pass
        if default_config_name is None and len(dataset_infos) == 1:
            default_config_name = next(iter(dataset_infos))