code: def fields(self) -> List[str]:
      return ["mean", "std"]
  
imports: import numpy
  from typing import List
  from typing import Tuple
  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 ImagenetNormalizeBlock obj's underlying member method code with example usage: obj.fields() and returns: list