code: def as_str(self, indent=""):
      res = indent + "[" + ", ".join(str(i) for i in iter(self)) + "]"
      return res
  
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 2 for calling the DataChunk obj's underlying member method code with example usage: obj.as_str(indent) and returns: res