[pybank] Add support for functions returning NULL

[Johan Dahlin <johan src gnome org>]

commit aed8aed09e3f87e0e53feb283a0217e4b2b171fe
Author: Tomeu Vizoso <tomeu sugarlabs org>
Date:   Tue May 5 15:22:43 2009 +0200

    Add support for functions returning NULL
---
 bank/bank-argument.c |   18 ++++++++++++------
 1 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/bank/bank-argument.c b/bank/bank-argument.c
index 06523a7..0920484 100644
--- a/bank/bank-argument.c
+++ b/bank/bank-argument.c
@@ -113,12 +113,18 @@ pyg_argument_to_pyobject(GArgument *arg, GITypeInfo *type_info)
     g_return_val_if_fail(type_info != NULL, NULL);
     type_tag = g_type_info_get_tag(type_info);
     if ( type_tag == GI_TYPE_TAG_INTERFACE ) {
-	GValue value;
-	GObject* obj = arg->v_pointer;
-	GType gtype = G_OBJECT_TYPE(obj);
-	value.g_type = gtype;
-	value.data[0].v_pointer = obj;
-	return pyg_value_as_pyobject(&value, FALSE);
+	if ( arg->v_pointer == NULL ) {
+	    obj = Py_None;
+	    Py_INCREF(obj);
+	    return obj;
+	} else {
+	    GValue value;
+	    GObject* obj = arg->v_pointer;
+	    GType gtype = G_OBJECT_TYPE(obj);
+	    value.g_type = gtype;
+	    value.data[0].v_pointer = obj;
+	    return pyg_value_as_pyobject(&value, FALSE);
+	}
     }
 
     switch (type_tag) {