def index_of(self, value):
        if self.sort_asc:
            redis_rank_fn = self.redis.zrank
        else:
            redis_rank_fn = self.redis.zrevrank
        key = self.get_key()
        result = redis_rank_fn(key, value)
        if result:
            result = int(result)
        elif result is None:
            raise ValueError(
                'Couldnt find item with value %s in key %s' % (value, key))
        return result
Make sure the default parameter is copied rather than passed by reference
dataset/ETHPy150Open tschellenbach/Stream-Framework/stream_framework/storage/redis/structures/sorted_set.py/RedisSortedSetCache.index_of--crossover with--dataset/ETHPy150Open bradjasper/django-jsonfield/jsonfield/tests.py/JSONFieldTest.test_pass_by_reference_pollution