How to determine the location of the puzzle from a given image?

Question

Python

There is an excellent article (sorry, I can’t insert links normally), habr.com/ru/company/joom/blog/445354/
judging by the information from the article, there is an excellent "SIFT" method that is resistant to scaling. But in the latest versions of opencv it is not available for licensing reasons:

http://qaru.site/questions/343954/opencv-python-and-sift-features

tell me which direction to go.
Initial data:
1. There is a certain number of scanned puzzles in the form of separate images.
2. There is a general image.
It is necessary (as I understand it):
1.1 "Recognize the puzzle" i.e. find something that describes the uniqueness of the contour.
1.2. Determine a certain uniqueness of the image on the puzzle
2. According to p.p. 1.1 and 1.2 find a place in the overall image.

Answer 1

But in latest versions of opencv it is not available due to licensing reasons

sift = cv2.xfeatures2d.SIFT_create()

Answer 2

When trying to execute...

Traceback (most recent call last):
  File "D:\my_programm_python\feature_detection\feature_detection.py", line 6, in <module>
    sift = cv2.xfeatures2d.SIFT_create()
cv2.error: OpenCV(3.4.8) C:\projects\opencv-python\opencv_contrib\modules\xfeatures2d\src\sift.cpp:1207: error: (-213:The function/feature is not implemented) This algorithm is patented and is excluded in this configuration; Set OPENCV_ENABLE_NONFREE CMake option and rebuild the library in function 'cv::xfeatures2d::SIFT::create'