How to add the "contrib" part to cv2

Hi, I'm using openCv 3.1.0 and python 2.4, both x64 version. I was looking at this https://docs.opencv.org/3.2.0/d1/dc5/tutorial_background_subtraction.html However none of those method are available (GMG, MOG, MOG2), and other one that I found with google, KNN is working. Then I learned that the new version of opencv splitted this way : the 'opencv cv2' and the 'contrib' version. what I need is in the contrib part. I installed opencv by downloading a .exe, which extracted a lot of stuff in a folder, an inside I found a cv2.pyd that I copy pasted in a folder of my python installation. How do I do the same for the contrib version? I've been looking for days. Thanks.