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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 _message_queryset(self, include_read=False):
 """ Return a queryset of messages for the request user """

        expire = timezone.now()


        qs = PersistentMessage.objects.\
        filter(user=self.get_user()).\
        filter(Q(expires=None) | Q(expires__gt=expire))
        if not include_read:
            qs = qs.exclude(read=True)
        return qs