Issue #6160: The bbox() method of Tkinter.Spinbox now returns a tuple of
integers instead of a string.  Based on patch by Guilherme Polo.
diff --git a/Lib/lib-tk/Tkinter.py b/Lib/lib-tk/Tkinter.py
index 529a3e4..6ad0cf1 100644
--- a/Lib/lib-tk/Tkinter.py
+++ b/Lib/lib-tk/Tkinter.py
@@ -3411,7 +3411,7 @@
         bounding box may refer to a region outside the
         visible area of the window.
         """
-        return self.tk.call(self._w, 'bbox', index)
+        return self._getints(self.tk.call(self._w, 'bbox', index)) or None
 
     def delete(self, first, last=None):
         """Delete one or more elements of the spinbox.