Run 2to3 over the Demo/ directory to shut up parse errors from 2to3 about lingering print statements.
diff --git a/Demo/tix/samples/OptMenu.py b/Demo/tix/samples/OptMenu.py
index 1d39420..2cf625a 100755
--- a/Demo/tix/samples/OptMenu.py
+++ b/Demo/tix/samples/OptMenu.py
@@ -40,7 +40,7 @@
     #        global variables "demo_opt_from" and "demo_opt_to". Otherwise
     #        the OptionMenu widget will complain about "unknown options"!
     #
-    for opt in options.keys():
+    for opt in list(options.keys()):
         from_file.add_command(opt, label=options[opt])
         to_file.add_command(opt, label=options[opt])
 
diff --git a/Demo/tix/tixwidgets.py b/Demo/tix/tixwidgets.py
index bf7102a..49d1e7f 100644
--- a/Demo/tix/tixwidgets.py
+++ b/Demo/tix/tixwidgets.py
@@ -166,7 +166,7 @@
                 try: tkMessageBox.showerror ('Error', text)
                 except: pass
                 self.exit = 1
-                raise SystemExit, 1
+                raise SystemExit(1)
 
     def destroy (self):
         self.root.destroy()