code: def __call__(self, img):
      noise = np.random.normal(self.mean, self.var**0.5, img.shape)
      img = np.clip(img + noise, 0, 255).astype(np.uint8)
      return img
  
imports: import math
  import numbers
  import random
  import cv2
  import numpy
  from paddle.vision.transforms import Compose, ColorJitter
label_desc: Use image node_id 2 for calling the CVGaussianNoise obj's underlying member method code with example usage: obj.__call__(img) and returns: img