diff --git a/fastlib2/mlpack/series_expansion/build.py b/fastlib2/mlpack/series_expansion/build.py
index 3e467d9254..25e46c19fe 100644
--- a/fastlib2/mlpack/series_expansion/build.py
+++ b/fastlib2/mlpack/series_expansion/build.py
@@ -8,7 +8,7 @@ librule(
                "mult_farfield_expansion_impl.h",
                "kernel_aux.h",
                "local_expansion.h",
-               "local_expansion_impl.h"
+               "local_expansion_impl.h",
                "mult_local_expansion.h",
                "mult_local_expansion_impl.h",
                "mult_series_expansion_aux.h",