def _cull(self):
        if self._cull_frequency == 0:
            self._cache.clear()
            self._expire_info.clear()
        else:
            doomed = [k for (i, k) in enumerate(self._cache) if i % self._cull_frequency == 0]
            for k in doomed:
                self.delete(k)
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-0.96/django/core/cache/backends/simple.py/CacheClass._cull/original