fix a lot of Tkinter imports
diff --git a/Demo/tkinter/guido/electrons.py b/Demo/tkinter/guido/electrons.py
index fdc558f..e3bf468 100755
--- a/Demo/tkinter/guido/electrons.py
+++ b/Demo/tkinter/guido/electrons.py
@@ -11,7 +11,7 @@
 # /usr/include/X11/bitmaps for samples); it is displayed as the
 # background of the animation.  Default is no bitmap.
 
-from Tkinter import *
+from tkinter import *
 import random