code: def fields(self) -> List[str]:
      return ["size"]
  
file_path: carefree-learn/cflearn/data/blocks/cv/crop.py
imports: import torch
  import numpy
  from typing import List
  from typing import Tuple
  from typing import Union
  from torchvision import transforms
  from cftool.types import np_dict_type
  from ....schema import IRuntimeDataBlock
  from ....constants import INPUT_KEY
label_desc: Use image node_id 2 for calling the RandomCropBlock obj's underlying member method code with example usage: obj.fields() and returns: list