def add_timeout(self, deadline, callback):
        timeout = _Timeout(deadline, stack_context.wrap(callback))
        heapq.heappush(self._timeouts, timeout)
        return timeout
Shortcut for the ``django.utils.timesince.timesince`` function of the
dataset/ETHPy150Open felipecruz/zmqpy/zmqpy/eventloop/ioloop.py/IOLoop.add_timeout--crossover with--dataset/ETHPy150Open django-notifications/django-notifications/notifications/models.py/Notification.timesince