Assign a value to a custom property?

Hello Once Again!
I am now looking for a way to assign values to custom properties using a button. The reason I wish to do this is so that I can have a small X button that the user can press to revert all values assigned back to 0 (Like the small X button below the Shape Keys window that resets all Shape Keys to 0). I am having trouble doing this as whenever I try to set the value it says I cannot assign to a literal.

http://gyazo.com/952415b8e22e8e6be8c1b44c0abd105b

I’m not really too sure how to do this but if anyone could help that would be great!

-UtopiaRules

the dot and comma in your example shouldn’t be there

bpy.context.object.data.[‘bla’] = 0

should read

bpy.context.object.data[‘bla’] = 0

facepalm
The one thing I didn’t try xD
Thanks so much for helping!! You’re now on my favourite people list :smiley: