@classmethod
    def _cache_key(cls, *args, **kwargs):
        return tuple(args) + tuple([(k, v) for k, v in kwargs.items()])
Test when a handler can't reach taskqueue.
dataset/ETHPy150Open OP2/PyOP2/pyop2/caching.py/Cached._cache_key--crossover with--dataset/ETHPy150Open GoogleCloudPlatform/appengine-mapreduce/python/test/mapreduce/handlers_test.py/MapperWorkerCallbackHandlerTest.testTaskqueueExceptionInHandler