diff --git a/firedrake/slate/slac/compiler.py b/firedrake/slate/slac/compiler.py
index 5a05eb3acf..a2ecc7cfbb 100644
--- a/firedrake/slate/slac/compiler.py
+++ b/firedrake/slate/slac/compiler.py
@@ -198,8 +198,7 @@ def generate_loopy_kernel(slate_expr, compiler_parameters=None):
                                                                  exterior_facets=(),
                                                                  interior_facets=(),
                                                                  exterior_facet_orientations=(),
-                                                                 interior_facet_orientations=(),
-                                             ),
+                                                                 interior_facet_orientations=(),),
                        coefficient_numbers=coefficient_numbers,
                        constant_numbers=constant_numbers,
                        needs_cell_facets=builder.bag.needs_cell_facets,