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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def new_reply(cls, thread, user, content):
 """ Create a new reply for an existing Thread. Mark thread as unread for all other participants, and mark thread as read by replier. """

        msg = cls.objects.create(thread=thread, sender=user, content=content)
        thread.userthread_set.exclude(user=user).update(deleted=False, unread=True)
        thread.userthread_set.filter(user=user).update(deleted=False, unread=False)
        message_sent.send(sender=cls, message=msg, thread=thread, reply=True)
        return msg