Only reference Tkinter._default_root when needed.
diff --git a/Lib/lib-tk/tkSimpleDialog.py b/Lib/lib-tk/tkSimpleDialog.py
index c297922..1e7ed46 100644
--- a/Lib/lib-tk/tkSimpleDialog.py
+++ b/Lib/lib-tk/tkSimpleDialog.py
@@ -119,10 +119,9 @@
                  minvalue = None, maxvalue = None,
                  parent = None):
 
-        from Tkinter import _default_root
-
         if not parent:
-            parent = _default_root
+            import Tkinter
+            parent = Tkinter._default_root
 
         self.prompt   = prompt
         self.minvalue = minvalue