def add(self, user):
        assert iwords.IChatClient.providedBy(user), (user,) % "%r is not a chat client"
        if user.name not in self.users:
            additions = []
            self.users[user.name] = user
            for p in self.users.itervalues():
                if p is not user:
                    d = defer.maybeDeferred(p.userJoined, self, user)
                    d.addErrback(self._ebUserCall, p=p)
                    additions.append(d)
            defer.DeferredList(additions).addCallback(self._cbUserCall)
        return defer.succeed(None)
dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/words/service.py/Group.add/swapped operands of `%`