diff --git a/frontends/src/jp/base.py b/frontends/src/jp/base.py
index 1cedb040..44f47754 100644
--- a/frontends/src/jp/base.py
+++ b/frontends/src/jp/base.py
@@ -755,7 +755,7 @@ class CommandBase(object):
 
         self._use_pubsub = kwargs.pop('use_pubsub', False)
         if self._use_pubsub:
-            flags = kwargs.pop('pubsub_flags', None)
+            flags = kwargs.pop('pubsub_flags', [])
             parents.add(self.host.make_pubsub_group(flags))
             self._pubsub_flags = flags