code: def color_norm(im, mean, std):
      """Performs per-channel normalization (used for training and testing)."""
      for i in range(3):
          im[:, :, i] = (im[:, :, i] - mean[i]) / std[i]
      return im
  
file_path: pycls/pycls/datasets/transforms.py
imports: from math import ceil, sqrt
  import cv2
  import numpy
  from PIL import Image
  from pycls.datasets.augment import make_augment
label_desc: Use image node_id 6 for calling a global function with example usage: color_norm(im, mean, std) and returns: im