Call function from another class

[Lars]

Hi
I'm trying to make an simple image viewer in wxPython and rotate an
image with a slider. The code at Pastebin is striped down at bit. The
class Frame(wx.Frame) is the main window, the function "def
CreateMenuBar" (l. 39) creates a menu, where the function "def onRotate
(self,event):" (l. 43) is called. The slider appear in at 2nd window,
class rotationSlider(wx.Frame).
My problem is what to do, when the Okay button is pressed in the
"rotationSlider" frame. How to get the slider value to my main window
and how to call a function to do the rotation. I tried something with
a global variable, but it would make no difference regarding the
function problem. Amongst the other things I've tried is to bind the
event of the 2nd/slider window closing (l. 46), but no.
Python code at Pastebin: http://pastebin.com/m7c24ec34

So some help on Classes and etc., would be appreciated.

/Lars