code: def __call__(self, img: np.ndarray) -> float:
      raise NotImplementedError(
          f"__call__ undefined in class {type(self)}"
      )
  
imports: import os
  import typing
  import torch
  import numpy
  import cv2
  from nevergrad.functions.base import UnsupportedExperiment
  from nevergrad.common.decorators import Registry
label_desc: Use image node_id 2 for calling the ImageLoss obj's underlying member method code with example usage: obj.__call__(img) without return types