title: "System error: new style getargs format but argument is not a tuple" when using cv2.blur
body: <p>I am just trying to apply a filter to an image using cv2, the opencv python bindings. Here is what my code look like:</p>
  
  <pre><code>im = cv2.imread('./test_imgs/zzzyj.jpg')
  cv2.imshow('Image', cv2.blur(im, 2)
  cv2.waitKey(0)
  </code></pre>
  
  <p>It's almost copy-and-paste from the <a href="http://docs.opencv.org/modules/imgproc/doc/filtering.html#void%20blur%28InputArray%20src,%20OutputArray%20dst,%20Size%20ksize,%20Point%20anchor,%20int%20borderType%29" rel="noreferrer">documentation</a>. However, it just doesn't work, with no more trace than this message:</p>
  
  <pre><code>SystemError: new style getargs format but argument is not a tuple
  </code></pre>
  
  <p>The same error occurs with GaussianBlur, but not with medianBlur. Any thoughts?</p>