initialize __doc__ to None
diff --git a/Objects/moduleobject.c b/Objects/moduleobject.c
index 8ab2f45..9d8e182 100644
--- a/Objects/moduleobject.c
+++ b/Objects/moduleobject.c
@@ -47,6 +47,8 @@
 		goto fail;
 	if (dictinsert(m->md_dict, "__name__", nameobj) != 0)
 		goto fail;
+	if (dictinsert(m->md_dict, "__doc__", None) != 0)
+		goto fail;
 	DECREF(nameobj);
 	return (object *)m;