code: def mse(img1, img2):
      return (
          (((img1 - img2)) ** 2)
          .view(img1.shape[0], -1)
          .mean(1, keepdim=True)
      )
  
label_desc: Use image node_id 1 for calling a global function with example usage: mse(img1, img2) and returns: unknown