title: Why can't use `cv2.cv.BoxPoints` in OpenCV (Python)?
body: <p>I am a beginner in OpenCV. I want to make bounding box around my detected marker.</p>
  
  <p>Can you tell me how can I do it with OpenCV (Python)?</p>
  
  <p>I'm using Python 3.6.3 with openCV</p>
  
  <pre><code>box =np.int0(cv2.cv.BoxPoints(marker))
  </code></pre>
  
  <p>Output:</p>
  
  <pre><code>Error showing cv2.cv2 has no module cv 
  </code></pre>