class_docstr: A lazily initialized sequence of datasets.
  
  This class provides a way to lazily generate and store the datasets
  linked to each experience. This class uses a generator to get the sequence
  of datasets but it can also be used with a more classic statically
  initialized Sequence (like a list).
  
  This class will also keep track of the targets and task labels field of the
  generated datasets.
docstr: Gets the length of the stream (number of experiences).
  
  :return: The length of the stream.
docstr_tok: ["Gets","the","length","of","the","stream","(","number","of","experiences",")",".",":","return",":","The","length","of","the","stream","."]
code: def __len__(self) -> int:
      """
      Gets the length of the stream (number of experiences).
  
      :return: The length of the stream.
      """
      return self._stream_length
  
file_path: avalanche/avalanche/benchmarks/scenarios/deprecated/lazy_dataset_sequence.py
imports: from collections import defaultdict
  from typing import Callable, Sequence, Iterable, Dict, Optional, Iterator, TypeVar, Union
  from typing_extensions import overload
  from avalanche.benchmarks.utils.data import AvalancheDataset
  from avalanche.benchmarks.utils.dataset_utils import manage_advanced_indexing
label_desc: Use image node_id 2 for calling the LazyDatasetSequence obj's underlying member method code with example usage: obj.__len__() and returns: self