fix todo doublon destinataires notifications

        return get_user_model().objects.filter(

                ( Q(subscribed_tasklists=self.task_list) & ~Q(unsubscribed_tasks=self)) \

              | (~Q(subscribed_tasklists=self.task_list) &  Q(subscribed_tasks=self))

        )

        ).order_by('pk').distinct('pk')

    def overdue_status(self):

        "Returns whether the Tasks's due date has passed or not."