Create customized xml for cv2.CascadeClassifier

Hello I am trying to build an OpenCV application for detecting all the cars in a video streaming. I am working in Windows10 and developed the following code:
import cv2
cap = cv2.VideoCapture( ‘videostreaming’)
car_cascade = cv2.CascadeClassifier( ‘cars.xml’)
I have the following question : how to create a cars.xml or xml file in cv2.CascadeClassifier for locating all the cars in my parking.
Regards

Hi
Please refer to this example cascade.
You can find much more examples in the internet.