fix a lot of Tkinter imports
diff --git a/Demo/tkinter/guido/AttrDialog.py b/Demo/tkinter/guido/AttrDialog.py
index 921c105..5508e3b 100755
--- a/Demo/tkinter/guido/AttrDialog.py
+++ b/Demo/tkinter/guido/AttrDialog.py
@@ -12,7 +12,7 @@
 # -- totally static, though different between PackDialog and WidgetDialog
 #    (but even that could be unified)
 
-from Tkinter import *
+from tkinter import *
 
 class Option: