code: def __len__(self) -> int:
      pass
  
file_path: vision/torchvision/prototype/datasets/utils/_dataset.py
imports: import abc
  import importlib
  import pathlib
  from typing import Any, Collection, Dict, Iterator, List, Optional, Sequence, Union
  from torchdata.datapipes.iter import IterDataPipe
  from torchvision.datasets.utils import verify_str_arg
  from ._resource import OnlineResource
label_desc: Use image node_id 6 for calling the Dataset obj's underlying member method code with example usage: obj.__len__() without return types