code: def size(self) -> Union[int, None]:
      return self._size
  
imports: import ctypes
  import pickle
  import uuid
  from io import BytesIO
  from typing import Tuple, Dict, List, Union
  from ..serialization import serialize, deserialize
  from ..utils import lazy_import, implements
  from .base import StorageBackend, StorageLevel, ObjectInfo, register_storage_backend
  from .core import StorageFileObject
  import numpy
  import pandas
label_desc: Use image node_id 3 for calling the CudaStorage obj's underlying member method code with example usage: obj.size() and returns: self