How to implement mouse gesture by python or pyqt ?

[iMath]

在 2013年1月8日星期二UTC+8上午8时44分20秒，iMath写道：
> It would be better to give me some examples .thanks in advance !
> 
> 
> 
> P.S. which module or lib are needed ?

what I wanna perhaps like this:
when a right mouse button is pressed and we go down and right with a cursor. As in letter 'L'. Our mouse gesture will close the window.
I googled such gesture examples on PyQt4 ,but hard to find one ,so your help will be greatly appreciated !
thanks inadvance !