hello im trying your code but i dont get good response from system

example

https://towardsdatascience.com/automatic-license-plate-detection-recognition-using-deep-learning-624def07eaaf

my only change its

contours, hierarchy = cv2.findContours(th3, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
to
_, contours, _ = cv2.findContours(th3, cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)