code: def __len__(self):
      try:
          return len(self._datapipe)
      except Exception as e:
          raise TypeError(
              f"{type(self).__name__} instance doesn't have valid length"
          ) from e
  
imports: import functools
  import pickle
  from typing import Dict, Callable, Optional, TypeVar, Generic, Iterator
  from torch.utils.data.datapipes._typing import _DataPipeMeta, _IterDataPipeMeta
  from torch.utils.data.datapipes._hook_iterator import _SnapshotState
  from torch.utils.data.datapipes.utils.common import _deprecation_warning, _iter_deprecated_functional_names, _map_deprecated_functional_names
  from torch.utils.data.dataset import Dataset, IterableDataset
label_desc: Use image node_id 4 for calling the _DataPipeSerializationWrapper obj's underlying member method code with example usage: obj.__len__() and returns: len