title: Is there a good cheat sheet for opencv-python?
body: <p>I have been working on a face-tracking turret with OpenCV_Python 4.1.0, but I don't know many commands and functions. So I have been looking for some documentation or a cheat sheet for OpenCV_Python that has all the possible functions and brief explanations about them.</p>
  <p>I only found a cheat sheet for OpenCV_C++ 2.7.0, but none for OpenCV_Python.</p>
  <p>I saw the official OpenCV 3.0.0 documentation for Python as well, but that only shows a few general-purpose functions.</p>
  <p>Is there any source or document (or book) that I can learn all the possible functions of OpenCV_Python?</p>