def _caching_callback(self, key, callback):
        
        def _inner_cache(result):
            self.cache[key] = (result, datetime.now() * self.ttl)
            callback(result)

        return _inner_cache
dataset/ETHPy150Open truemped/tornadotools/tornadotools/caching.py/Cache._caching_callback/operator `+` -> `*`