How can I get Geany to autocomplete an object's constraints?
For example, I type:
self.window.set_position(gtk.WIN_
And I want the list of possible constraints to show up such as WIN_POS_NONE and WIN_POS_CENTER etc.  
NOTE: CTRL+SPACE or CTRL+SHIFT+SPACE does not show constraints.
Autocompletion works fine for functions and symbols, just not constraints, unless I've used it once already before.  This saves me the time of looking at documentation.  Sometimes I can partially remember the constraint, and it would be nice to be able to browse the options.
I would basically like it to work like it does in Sublime Text, which is a near-perfect editor for me, but I'm looking for something free/opensource to use.
EDIT: I've also tried Ninja-IDE which can also display constraints, but it locks up sometimes and is not as lightweight as Geany...
EDIT 2: I'm not looking for an alternative to Geany, I'm looking to make this functionality work via a mod or plug-in.
From what I have been able to find, this is beyond what Geany can do.  I asked how to get Geany to do this and I am not looking for any alternatives to Geany, nor am I interested in using anything else.  Therefore, this is the accepted answer, unless someone posts a way to make it work in Geany, at that point I will change the accepted answer.
Geany autocomplete Python constraints