code: def normalize(im: np.ndarray, mean: float, std: float) -> np.ndarray:
      """
      Normalize the input image.
  
      Args:
          im(np.ndarray): Input image.
          mean(float): The mean value of normalization.
          std(float): The standard deviation value of normalization.
      """
      im = im.astype(np.float32, copy=False) / 255.0
      im -= mean
      im /= std
      return im
  
file_path: PaddleHub/paddlehub/vision/functional.py
imports: import os
  from typing import List, Union
  import cv2
  import PIL
  import numpy
label_desc: Use image node_id 1 for calling a global function with example usage: normalize(im, mean, std) and returns: im