old_contents: import numpy as np
  import cv2
  
  img = cv2.imread('media/img.jpg', cv2.WINDOW_NORMAL)
  cv2.imshow('image', img)
  k = cv2.waitKey(0)
  if k == 27:             # ESC key to exit
      cv2.destroyAllWindows()
  elif k == ord('s'):     # 's' key to save & exit
      cv2.imwrite('media/gen_img_gray.png', img)
      cv2.destroyAllWindows()
  
new_contents: import numpy as np
  import cv2
  
  img = cv2.imread('media/img.jpg', cv2.WINDOW_NORMAL)
  cv2.imshow('image', img)
  k = cv2.waitKey(0)
  if k == 27:             # ESC key to exit
      cv2.destroyAllWindows()
  elif k == ord('s'):     # 's' key to save & exit
      cv2.imwrite('media/gen_img_gray.png', img)
      cv2.destroyAllWindows()
  
  #test
  
subject: test :vertical_traffic_light: