--- a/src/plugins/plugin_xep_0045.py	Fri Nov 27 17:53:13 2015 +0100
+++ b/src/plugins/plugin_xep_0045.py	Sun Nov 29 22:47:52 2015 +0100
@@ -380,10 +380,12 @@
         # > /usr/local/lib/python2.7/dist-packages/twisted/internet/defer.py(480)_startRunCallbacks()
         # -> raise AlreadyCalledError(extra)
 
-    def _join(self, room_jid_s, nick, options={}, profile_key=C.PROF_KEY_NONE):
+    def _join(self, room_jid_s, nick, options=None, profile_key=C.PROF_KEY_NONE):
         """join method used by bridge: use the join method, but doesn't return any deferred
         @return: unicode (the room bare)
         """
+        if options is None:
+            options = {}
         profile = self.host.memory.getProfileName(profile_key)
         if not self.checkClient(profile):
             return