Code completion is not working for OpenCV and Python

I am using Ubuntu 14.04. I have installed OpenCV using Adrian Rosebrock's guide. I am also using PyCharm for programming python and opencv.

My problem is that I can use code completion for cv2 modules but code completion wont work for instances initiated from cv2. An example is shown below.

This one works.

But this one wouldn't.

There is no run time error when I write my program as expected. Such that cap.isOpened() works without an error.

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