code: def _normalize_pixelwise(img: np.ndarray) -> np.ndarray:
      """Normalize the pixel values of an image.
  
      Parameters
      ----------
      img: np.ndarray
          The image to normalize.
  
      Returns
      -------
      np.ndarray
          The normalized image.
      """
      s = img.sum(axis=2)
      return np.array(
          [
              np.divide(
                  img[:, :, i],
                  s,
                  out=np.zeros_like(img[:, :, i], dtype="float64"),
                  where=s != 0,
              )
              for i in range(3)
          ]
      )
  
imports: from typing import Dict, List, Tuple
  import numpy
  from cv2 import CV_64F, Laplacian
  from skimage.color import rgb2gray
label_desc: Use image node_id 13 for calling a global function with example usage: _normalize_pixelwise(img) and returns: np