class_docstr: Normlize image by given mean and std.
      
code: def __init__(self, mean, std):
      self.__mean = mean
      self.__std = std
  
file_path: PaddleHub/modules/image/depth_estimation/MiDaS_Small/transforms.py
imports: import numpy
  import cv2
label_desc: Use image node_id 1 to create a new NormalizeImage object from inherited base classes: object with example: obj = NormalizeImage(mean, std)