http_proxy=http://127.0.0.1:8080 https_proxy=http://127.0.0.1:8080 brew install opencv --without-python --with-python3
#cd to virt env
lib/python3.7/site-packages/
ln -s /usr/local/lib/python3.7/site-packages/cv2.cpython-37m-darwin.so cv2.so
ln /usr/local/lib/python3.7/site-packages/cv2.cpython-37m-darwin.so cv2.so