--- a/rollbot.py	Sun May 15 11:38:32 2016 +0800
+++ b/rollbot.py	Sun May 15 21:39:48 2016 +0800
@@ -136,7 +136,10 @@
 
     def muc_invite(self, invite):
         room = invite['from']
-        password = '' # https://github.com/fritzy/SleekXMPP/issues/409
+        # https://github.com/fritzy/SleekXMPP/issues/409
+        ns = 'http://jabber.org/protocol/muc#user'
+        pel = invite.find('{%(ns)s}x/{%(ns)s}password' % {'ns': ns})
+        password = pel.text if pel is not None else ''
         self.plugin['xep_0045'].joinMUC(room, self.nick, password=password, wait=True)
 
     def muc_direct_invite(self, invite):