title: Python: Cannot find and install python module 'video'
body: <p>I am using Python 3.6. I tried to run the OpenCV optical flow code:
  <a href="https://github.com/opencv/opencv/blob/master/samples/python/opt_flow.py" rel="noreferrer">https://github.com/opencv/opencv/blob/master/samples/python/opt_flow.py</a></p>
  
  <p>and there was an error:</p>
  
  <pre><code>ModuleNotFoundError: No module named 'video'
  </code></pre>
  
  <p>I thought the 'video' module must be missing. So, I run</p>
  
  <pre><code>pip install video
  </code></pre>
  
  <p>in the command line, but it gave me this error:</p>
  
  <pre><code>Collecting video
    Could not find a version that satisfies the requirement video (from versions: )
  No matching distribution found for video
  </code></pre>
  
  <p>Could anyone advise on how to solve this problem? How to find where are the OpenCV modules installed in local drive?</p>