diff --git a/tools/test/topos/optical2.py b/tools/test/topos/optical2.py
index bf4aba5..36cdbad 100644
--- a/tools/test/topos/optical2.py
+++ b/tools/test/topos/optical2.py
@@ -16,7 +16,7 @@
 
 class NullLink( Link ):
     "A dummy link that doesn't touch either interface"
-    def makeIntfPair( cls, intf1, intf2 ):
+    def makeIntfPair( cls, intf1, intf2, *args, **kwargs ):
         pass
     def delete( self ):
         pass