OpenCV: AttributeError: module 'cv2' has no attribute 'face'

I am creating a face recognition system using Python and OpenCV on these versions:

When I try to train the face recognizer:

face_recognizer = cv2.face.createLBPHFaceRecognizer()

I get this error:

AttributeError: module 'cv2' has no attribute 'face'

Update:

I've tried to do this:

pip install opencv_python‑3.3.0+contrib‑cp36‑cp36m‑win_amd64.whl

Also:

conda install -c menpo opencv3=3.3.0

And I still have the error.

Solution

I found the solution to my issue, you have to follow this tutorial OpenCV with extra modules.

The essential steps are:

Go to C:/PythonXX/lib/site-packeges (the site-packages folder where your python is installed), and delete cv2.pyd if present.
Download OpenCV with extra modules
Create a Visual Studio project with CMake
Open Python IDLE and enter import cv2. If there is no error, then the installation is successful.