title: How to update Opencv3.3?
body: <p>I already have installed OpenCV 3.3 with python3 on my Macbook in a virtual environment. I want to update to OpenCV 3.4. I had installed OpenCV 3.3 by following <a href="https://www.pyimagesearch.com/2016/12/19/install-opencv-3-on-macos-with-homebrew-the-easy-way/" rel="nofollow noreferrer">https://www.pyimagesearch.com/2016/12/19/install-opencv-3-on-macos-with-homebrew-the-easy-way/</a> tutorial.<br>
  How to do this?</p>