More codestring -> codebytes.
diff --git a/Lib/test/test_gettext.py b/Lib/test/test_gettext.py
index e26b30a..0023941 100644
--- a/Lib/test/test_gettext.py
+++ b/Lib/test/test_gettext.py
@@ -65,13 +65,13 @@
         if not os.path.isdir(LOCALEDIR):
             os.makedirs(LOCALEDIR)
         fp = open(MOFILE, 'wb')
-        fp.write(base64.decodestring(GNU_MO_DATA))
+        fp.write(base64.decodebytes(GNU_MO_DATA))
         fp.close()
         fp = open(UMOFILE, 'wb')
-        fp.write(base64.decodestring(UMO_DATA))
+        fp.write(base64.decodebytes(UMO_DATA))
         fp.close()
         fp = open(MMOFILE, 'wb')
-        fp.write(base64.decodestring(MMO_DATA))
+        fp.write(base64.decodebytes(MMO_DATA))
         fp.close()
         self.env = support.EnvironmentVarGuard()
         self.env['LANGUAGE'] = 'xx'