Installing OpenCV version 3.4.2 and above raise a python checking error

[OronG13]

In case I'm trying to install OpenCV version 3.4.2 or 3.4.4 for example the Python checking which performed as the last step of the installation process is failed due to unresolved symbol "...dnn..." despite the fact that the cv2.so file was generated and the import cv2 command identify it.

Please advise.