title: python opencv imwrite ... can't find params
body: <p>I am using opencv with python. I wanted to do an cv2.imwrte:</p>
  
  <pre><code>cv2.imwrite('myimage.png', my_im)
  </code></pre>
  
  <p>The only problem is that opencv does not recognize the params constants:</p>
  
  <pre><code>cv2.imwrite('myimage.png', my_im, cv2.CV_IMWRITE_PNG_COMPRESSION, 0)
  </code></pre>
  
  <p>It cannot find CV_IMWRITE_PNG_COMPRESSION at all. Any ideas?</p>