diff --git a/multibuild.py b/multibuild.py
index cab1ca7..7f2b7e6 100644
--- a/multibuild.py
+++ b/multibuild.py
@@ -57,7 +57,7 @@ def add_child_sh_steps(build_factory, directory=".buildbot"):
         steps.FileDownload(
             name="Upload keystore",
             workerdest="/var/lib/buildbot/keystore",
-            mastersrc=util.Interpolate("keystore/%(prop:jobname)s.keystore")
+            mastersrc=util.Interpolate("keystore/%(prop:jobname)s.keystore"),
             doStepIf=should_build_sign,
             hideStepIf=True,
             mode=0o600