class_docstr: Base implementation of a Continual Learning classification benchmark.
  
  For more info, please refer to the base class :class:`DatasetScenario`.
code: def classes_in_experience(self):
      return _LazyStreamClassesInClassificationExps(self)
  
imports: from typing import Callable, TypeVar, Union, Sequence, Optional, Iterable, List, Set, Tuple, Mapping, overload, TYPE_CHECKING
  import warnings
  from avalanche.benchmarks.scenarios.deprecated import AbstractClassTimelineExperience
  from avalanche.benchmarks.scenarios.deprecated.dataset_scenario import ClassesTimelineCLScenario, FactoryBasedStream, TStreamsUserDict
  from avalanche.benchmarks.utils.dataset_utils import manage_advanced_indexing
label_desc: Use image node_id 2 for calling the ClassificationScenario obj's underlying member method code with example usage: obj.classes_in_experience() and returns: _LazyStreamClassesInClassificationExps