diff --git a/examples/euler_2d/shock_forward_step.py b/examples/euler_2d/shock_forward_step.py
index 406e0c285..6fc9f9e90 100755
--- a/examples/euler_2d/shock_forward_step.py
+++ b/examples/euler_2d/shock_forward_step.py
@@ -50,7 +50,7 @@
         raise
 
 
-def incoming_shock(state,dim,t,qbc,num_ghost):
+def incoming_shock(state,dim,t,qbc,auxbc,num_ghost):
     """
     Incoming shock at left boundary.
     """