code: def fetch(bank, key):
      '''
      Fetch data from the Redis cache.
      '''
      redis_server = _get_redis_server()
      redis_key = _get_key_redis_key(bank, key)
      redis_value = None
      try:
          redis_value = redis_server.get(redis_key)
      except (RedisConnectionError, RedisResponseError) as rerr:
          mesg = 'Cannot fetch the Redis cache key {rkey}: {rerr}'.format(rkey=redis_key,
                                                                          rerr=rerr)
          log.error(mesg)
          raise SaltCacheError(mesg)
      if redis_value is None:
          return {}
      return __context__['serial'].loads(redis_valuef fetch(bank, key):
      '''
      Fetch data from the Redis cache.
      '''
      redis_server = _get_redis_server()
      redis_key = _get_key_redis_key(bank, key)
      redis_value = None
      try:
          redis_value = redis_server.get(redis_key)
      except (RedisConnectionError, RedisResponseError) as rerr:
          mesg = 'Cannot fetch the Redis cache key {rkey}: {rerr}'.format(rkey=redis_key,
                                                                          rerr=rerr)
          log.error(mesg)
          raise SaltCacheError(mesg)
      if redis_value is None:
          return {}
      return __context__['serial'].loads(redis_value)
docs: Fetch data from the Redis cache.