code: def __init__(
      self, benchmark: DetectionScenario, stream: str = "train"
  ):
      self._benchmark = benchmark
      self._stream = stream
  
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 1 to create a new _LazyClassesInDetectionExps object from inherited base classes: Sequence with example: obj = _LazyClassesInDetectionExps(benchmark, stream)