diff -aur pygtksourceview-2.10.1/gtksourceview2.override pygtksourceview-2.10.1.new/gtksourceview2.override
--- pygtksourceview-2.10.1/gtksourceview2.override	2010-03-28 23:18:25.000000000 +1100
+++ pygtksourceview-2.10.1.new/gtksourceview2.override	2011-11-08 12:34:32.827283717 +1100
@@ -1249,7 +1249,7 @@
 
     if (!PyArg_ParseTupleAndKeywords(args,
                                      kwargs,
-                                     "Os:GtkSourceBuffer.get_context_classes_at_iter",
+                                     "O:GtkSourceBuffer.get_context_classes_at_iter",
                                      kwlist,
                                      &py_iter))
         return NULL;