Index: lib2to3/fixes/fix_imports.py
===================================================================
--- lib2to3/fixes/fix_imports.py	(revision 63516)
+++ lib2to3/fixes/fix_imports.py	(working copy)
@@ -114,6 +114,7 @@
                         'OptionMenu', 'Image', 'PhotoImage', 'BitmapImage',
                         'image_names', 'image_types', 'Spinbox', 'LabelFrame',
                         'PanedWindow', 'Studbutton', 'Tributton']),
+           "markupbase": ("_markupbase", ["ParserBase"]),
            }