[PyQt] How to create a user-resizeable widget?

[Noam Raphael]

Hello,

I want to create in my application a bar on the left, which allows
navigation, and a main area right of it. I want the user to be able to
change the width of the navigation area. How do I do it?

(I've seen that docks can do it, but they seem too much for me - I
only want a handle between two areas of the window that the user can
drag, I don't need crazy floating windows)

Thanks,
Noam