C++ and Python

#Description:
#Create a undo/redo callback using maya python api
#Usage:
#Call the undoRedoCallback function with "add" to create the undo/redo callbacks. Or call the 
#undoRedoCallback function with "remove" as argument to remove the created callbacks.
#
#Info:
#Reference from undoRedoMsgCmd.cpp exemple
#By Rosenio Pinto
#kenio3d@gmail.com

import maya.OpenMaya as om

def undoTest(*args):
    print 'Checking Undo callback'
    
def redoTest(*args):
    print 'Checking ReDo callback'

def undoRedoCallback(arg):
    global callbackIDs
    
    undoStr = str('Undo')
    redoStr = str('Redo')
    Null = om.MObject()
    
    if arg == 'add':

        undoID = om.MEventMessage.addEventCallback(undoStr, undoTest, Null)
        redoID = om.MEventMessage.addEventCallback(redoStr, redoTest, Null)
        
        callbackIDs = [undoID, redoID]
    
    elif arg == 'remove':
        try:
            for i in callbackIDs:
                om.MEventMessage.removeCallback(i)
        except:
            print 'There is no ID to delete'

    else:
        print 'The argument must be "add" or "remove"'