Python could not detect OpenCv installed in my system
Likely has to do with where the package was installed. If you used apt-get, I would recommend removing and trying with pip install opencv-python. Aside from that, you can also try running sudo python3 and then importing.
hope that helps!
I installed opencv 4.3.0 from the source. It was installed sucessfully. 
pkg-config --modversion opencv4 gives the output 4.3.0 . But when i try to import cv2 module in pythone it says cv2 module not found. I have Linux(Debian) in my system with python 3.8.