code: def __str__(self):
      return (
          "["
          + ", ".join([str(self[idx]) for idx in range(len(self))])
          + "]"
      )
  
imports: from typing import Iterable, Mapping, Optional, Sequence, Set, Tuple, TypeVar, List, Callable, Union, overload
  import warnings
  from avalanche.benchmarks.scenarios.deprecated.dataset_scenario import ClassesTimelineCLScenario, DatasetScenario, FactoryBasedStream, TStreamsUserDict
  from avalanche.benchmarks.scenarios.deprecated import AbstractClassTimelineExperience
  from avalanche.benchmarks.utils.data import AvalancheDataset
  from avalanche.benchmarks.utils.dataset_utils import manage_advanced_indexing
  from avalanche.benchmarks.utils.detection_dataset import DetectionDataset
label_desc: Use image node_id 6 for calling the _LazyClassesInDetectionExps obj's underlying member method code with example usage: obj.__str__() and returns: unknown