def _find_keys_raw(self, prefix):
        raise NotImplementedError()
Cancel a L{Deferred} if it does not have a result available within the
dataset/ETHPy150Open mariocesar/sorl-thumbnail/sorl/thumbnail/kvstores/base.py/KVStoreBase._find_keys_raw--crossover with--dataset/ETHPy150Open ClusterHQ/flocker/flocker/_twisted.py/timeoutDeferred