How to use the fakeredis._server.SimpleString function in fakeredis

def type(self, key):
        if key.value is None:
            return SimpleString(b'none')
        elif isinstance(key.value, bytes):
            return SimpleString(b'string')
        elif isinstance(key.value, list):
            return SimpleString(b'list')
        elif isinstance(key.value, set):
            return SimpleString(b'set')
        elif isinstance(key.value, ZSet):
            return SimpleString(b'zset')
        elif isinstance(key.value, dict):
            return SimpleString(b'hash')
        else:
            assert False      # pragma: nocover

def type(self, key):
        if key.value is None:
            return SimpleString(b'none')
        elif isinstance(key.value, bytes):
            return SimpleString(b'string')
        elif isinstance(key.value, list):
            return SimpleString(b'list')
        elif isinstance(key.value, set):
            return SimpleString(b'set')
        elif isinstance(key.value, ZSet):
            return SimpleString(b'zset')
        elif isinstance(key.value, dict):
            return SimpleString(b'hash')
        else:
            assert False      # pragma: nocover

def _convert_redis_result(self, lua_runtime, result):
        if isinstance(result, (bytes, int, long)):
            return result
        elif isinstance(result, SimpleString):
            return lua_runtime.table_from({b"ok": result.value})
        elif result is None:
            return False
        elif isinstance(result, list):
            converted = [
                self._convert_redis_result(lua_runtime, item)
                for item in result
            ]
            return lua_runtime.table_from(converted)
        elif isinstance(result, redis.ResponseError):
            raise result
        else:
            raise RuntimeError("Unexpected return type from redis: {}".format(type(result)))

def type(self, key):
        if key.value is None:
            return SimpleString(b'none')
        elif isinstance(key.value, bytes):
            return SimpleString(b'string')
        elif isinstance(key.value, list):
            return SimpleString(b'list')
        elif isinstance(key.value, set):
            return SimpleString(b'set')
        elif isinstance(key.value, ZSet):
            return SimpleString(b'zset')
        elif isinstance(key.value, dict):
            return SimpleString(b'hash')
        else:
            assert False      # pragma: nocover

def type(self, key):
        if key.value is None:
            return SimpleString(b'none')
        elif isinstance(key.value, bytes):
            return SimpleString(b'string')
        elif isinstance(key.value, list):
            return SimpleString(b'list')
        elif isinstance(key.value, set):
            return SimpleString(b'set')
        elif isinstance(key.value, ZSet):
            return SimpleString(b'zset')
        elif isinstance(key.value, dict):
            return SimpleString(b'hash')
        else:
            assert False      # pragma: nocover

def _convert_lua_result(self, result, nested=True):
        from lupa import lua_type
        if lua_type(result) == 'table':
            for key in (b'ok', b'err'):
                if key in result:
                    msg = self._convert_lua_result(result[key])
                    if not isinstance(msg, bytes):
                        # TODO: put in a constant for this
                        raise redis.ResponseError("wrong number or type of arguments")
                    if key == b'ok':
                        return SimpleString(msg)
                    elif nested:
                        return redis.ResponseError(msg)
                    else:
                        raise redis.ResponseError(msg)
            # Convert Lua tables into lists, starting from index 1, mimicking the behavior of StrictRedis.
            result_list = []
            for index in itertools.count(1):
                if index not in result:
                    break
                item = result[index]
                result_list.append(self._convert_lua_result(item))
            return result_list
        elif isinstance(result, six.text_type):
            return six.ensure_binary(result)
        elif isinstance(result, float):
            return int(result)

class SimpleString(object):
    def __init__(self, value):
        assert isinstance(value, bytes)
        self.value = value


class NoResponse(object):
    """Returned by pub/sub commands to indicate that no response should be returned"""
    pass


OK = SimpleString(b'OK')
QUEUED = SimpleString(b'QUEUED')
PONG = SimpleString(b'PONG')
BGSAVE_STARTED = SimpleString(b'Background saving started')


if six.PY2:
    def isfinite(value):
        return not math.isinf(value) and not math.isnan(value)

    # Not the same as six.byte2int, which takes a bytes in both Python 2+3.
    # This takes an integer in Python 3.
    def byte_to_int(value):
        return ord(value)
else:
    def isfinite(value):
        return math.isfinite(value)

    def byte_to_int(value):
        assert isinstance(value, int)

def type(self, key):
        if key.value is None:
            return SimpleString(b'none')
        elif isinstance(key.value, bytes):
            return SimpleString(b'string')
        elif isinstance(key.value, list):
            return SimpleString(b'list')
        elif isinstance(key.value, set):
            return SimpleString(b'set')
        elif isinstance(key.value, ZSet):
            return SimpleString(b'zset')
        elif isinstance(key.value, dict):
            return SimpleString(b'hash')
        else:
            assert False      # pragma: nocover