def unsubscribe(self, field, callable_):
        self._subscribers[field].remove(weakref.ref(callable_))
Gets called periodically to remove old data that is useless beyond given timestamp.
dataset/ETHPy150Open VisTrails/VisTrails/vistrails/core/configuration.py/ConfigurationObject.unsubscribe--crossover with--dataset/ETHPy150Open Yelp/elastalert/elastalert/ruletypes.py/RuleType.garbage_collect