Remove prefix attribute

main.py

@@ -211,7 +211,6 @@ class AngelBot(ClientXMPP):
     def __init__(self, jid, password, nick="angel", autojoin=None):
         ClientXMPP.__init__(self, jid, password)
         self.jid = jid
-        self.prefix = prefix
         self.nick = nick
         self.autojoin = autojoin or []
         self.add_event_handler("session_start", self.session_start)