code: def __str__(self):
      return (
          "["
          + ", ".join([str(self[idx]) for idx in range(len(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 6 for calling the _LazyClassesInClassificationExps obj's underlying member method code with example usage: obj.__str__() and returns: unknown