code: def __len__(self) -> int:
      return 64
  
file_path: determined/examples/features/unmanaged/advanced/checkpoints_advanced.py
imports: from typing import Tuple
  import torch
  from determined.experimental import core_v2
label_desc: Use image node_id 2 for calling the IdentityDataset obj's underlying member method code with example usage: obj.__len__() and returns: int