How to use the grpclib.const.Cardinality function in grpclib

def __mapping__(self) -> typing.Dict[str, grpclib.const.Handler]:
        return {
            '/dummy.DummyService/UnaryUnary': grpclib.const.Handler(
                self.UnaryUnary,
                grpclib.const.Cardinality.UNARY_UNARY,
                dummy_pb2.DummyRequest,
                dummy_pb2.DummyReply,
            ),
            '/dummy.DummyService/UnaryStream': grpclib.const.Handler(
                self.UnaryStream,
                grpclib.const.Cardinality.UNARY_STREAM,
                dummy_pb2.DummyRequest,
                dummy_pb2.DummyReply,
            ),
            '/dummy.DummyService/StreamUnary': grpclib.const.Handler(
                self.StreamUnary,
                grpclib.const.Cardinality.STREAM_UNARY,
                dummy_pb2.DummyRequest,
                dummy_pb2.DummyReply,
            ),
            '/dummy.DummyService/StreamStream': grpclib.const.Handler(
                self.StreamStream,
                grpclib.const.Cardinality.STREAM_STREAM,
                dummy_pb2.DummyRequest,
                dummy_pb2.DummyReply,
            ),

buf.add('')
        buf.add('class {}Stub:', service.name)
        with buf.indent():
            buf.add('')
            buf.add('def __init__(self, channel: {}.{}) -> None:'
                    .format(client.__name__, client.Channel.__name__))
            with buf.indent():
                for method in service.methods:
                    name, cardinality, request_type, reply_type = method
                    full_name = '/{}/{}'.format(service_name, name)
                    method_cls: type
                    if cardinality is const.Cardinality.UNARY_UNARY:
                        method_cls = client.UnaryUnaryMethod
                    elif cardinality is const.Cardinality.UNARY_STREAM:
                        method_cls = client.UnaryStreamMethod
                    elif cardinality is const.Cardinality.STREAM_UNARY:
                        method_cls = client.StreamUnaryMethod
                    elif cardinality is const.Cardinality.STREAM_STREAM:
                        method_cls = client.StreamStreamMethod
                    else:
                        raise TypeError(cardinality)
                    method_cls = cast(type, method_cls)  # FIXME: redundant
                    buf.add('self.{} = {}.{}('.format(name, client.__name__,
                                                      method_cls.__name__))
                    with buf.indent():
                        buf.add('channel,')
                        buf.add('{!r},'.format(full_name))
                        buf.add('{},', request_type)
                        buf.add('{},', reply_type)
                    buf.add(')')
    return buf.content()

),
            '/helloworld.Greeter/UnaryStreamGreeting': grpclib.const.Handler(
                self.UnaryStreamGreeting,
                grpclib.const.Cardinality.UNARY_STREAM,
                helloworld.helloworld_pb2.HelloRequest,
                helloworld.helloworld_pb2.HelloReply,
            ),
            '/helloworld.Greeter/StreamUnaryGreeting': grpclib.const.Handler(
                self.StreamUnaryGreeting,
                grpclib.const.Cardinality.STREAM_UNARY,
                helloworld.helloworld_pb2.HelloRequest,
                helloworld.helloworld_pb2.HelloReply,
            ),
            '/helloworld.Greeter/StreamStreamGreeting': grpclib.const.Handler(
                self.StreamStreamGreeting,
                grpclib.const.Cardinality.STREAM_STREAM,
                helloworld.helloworld_pb2.HelloRequest,
                helloworld.helloworld_pb2.HelloReply,
            ),

),
            '/ClientMaster.AngelCleintMaster/Clock': grpclib.const.Handler(
                self.Clock,
                grpclib.const.Cardinality.UNARY_UNARY,
                client_master_pb2.ClockReq,
                client_master_pb2.ClockResp,
            ),
            '/ClientMaster.AngelCleintMaster/GetClockMap': grpclib.const.Handler(
                self.GetClockMap,
                grpclib.const.Cardinality.UNARY_UNARY,
                client_master_pb2.GetClockMapReq,
                client_master_pb2.GetClockMapResp,
            ),
            '/ClientMaster.AngelCleintMaster/GetGlobalBatchSize': grpclib.const.Handler(
                self.GetGlobalBatchSize,
                grpclib.const.Cardinality.UNARY_UNARY,
                common_pb2.VoidReq,
                client_master_pb2.GetGlobalBatchResp,
            ),
            '/ClientMaster.AngelCleintMaster/CompleteTask': grpclib.const.Handler(
                self.CompleteTask,
                grpclib.const.Cardinality.UNARY_UNARY,
                common_pb2.CompleteTaskReq,
                common_pb2.VoidResp,
            ),

def __mapping__(self) -> typing.Dict[str, grpclib.const.Handler]:
        return {
            '/helloworld.Greeter/UnaryUnaryGreeting': grpclib.const.Handler(
                self.UnaryUnaryGreeting,
                grpclib.const.Cardinality.UNARY_UNARY,
                streaming.helloworld_pb2.HelloRequest,
                streaming.helloworld_pb2.HelloReply,
            ),
            '/helloworld.Greeter/UnaryStreamGreeting': grpclib.const.Handler(
                self.UnaryStreamGreeting,
                grpclib.const.Cardinality.UNARY_STREAM,
                streaming.helloworld_pb2.HelloRequest,
                streaming.helloworld_pb2.HelloReply,
            ),
            '/helloworld.Greeter/StreamUnaryGreeting': grpclib.const.Handler(
                self.StreamUnaryGreeting,
                grpclib.const.Cardinality.STREAM_UNARY,
                streaming.helloworld_pb2.HelloRequest,
                streaming.helloworld_pb2.HelloReply,
            ),
            '/helloworld.Greeter/StreamStreamGreeting': grpclib.const.Handler(
                self.StreamStreamGreeting,
                grpclib.const.Cardinality.STREAM_STREAM,
                streaming.helloworld_pb2.HelloRequest,
                streaming.helloworld_pb2.HelloReply,
            ),

buf.add('')
            buf.add('def __mapping__(self) -> typing.Dict[str, {}.{}]:',
                    const.__name__,
                    const.Handler.__name__)
            with buf.indent():
                buf.add('return {{')
                with buf.indent():
                    for method in service.methods:
                        name, cardinality, request_type, reply_type = method
                        full_name = '/{}/{}'.format(service_name, name)
                        buf.add("'{}': {}.{}(", full_name, const.__name__,
                                const.Handler.__name__)
                        with buf.indent():
                            buf.add('self.{},', name)
                            buf.add('{}.{}.{},', const.__name__,
                                    const.Cardinality.__name__,
                                    cardinality.name)
                            buf.add('{},', request_type)
                            buf.add('{},', reply_type)
                        buf.add('),')
                buf.add('}}')

        buf.add('')
        buf.add('')
        buf.add('class {}Stub:', service.name)
        with buf.indent():
            buf.add('')
            buf.add('def __init__(self, channel: {}.{}) -> None:'
                    .format(client.__name__, client.Channel.__name__))
            with buf.indent():
                for method in service.methods:
                    name, cardinality, request_type, reply_type = method

else:
                await stream.send_request(end=True)
            reply = await stream.recv_message()
        assert reply is not None
        return reply


class StreamStreamMethod(ServiceMethod[_SendType, _RecvType]):
    """
    Represents STREAM-STREAM gRPC method type.

    .. autocomethod:: __call__
    .. autocomethod:: open
        :async-with:
    """
    _cardinality = Cardinality.STREAM_STREAM

    async def __call__(
        self,
        messages: Sequence[_SendType],
        *,
        timeout: Optional[float] = None,
        metadata: Optional[_MetadataLike] = None,
    ) -> List[_RecvType]:
        """Coroutine to perform defined call.

        :param messages: sequence of messages
        :param float timeout: request timeout (seconds)
        :param metadata: custom request metadata, dict or list of pairs
        :return: sequence of messages
        """
        async with self.open(timeout=timeout, metadata=metadata) as stream:

buf.add('),')
                buf.add('}}')

        buf.add('')
        buf.add('')
        buf.add('class {}Stub:', service.name)
        with buf.indent():
            buf.add('')
            buf.add('def __init__(self, channel: {}.{}) -> None:'
                    .format(client.__name__, client.Channel.__name__))
            with buf.indent():
                for method in service.methods:
                    name, cardinality, request_type, reply_type = method
                    full_name = '/{}/{}'.format(service_name, name)
                    method_cls: type
                    if cardinality is const.Cardinality.UNARY_UNARY:
                        method_cls = client.UnaryUnaryMethod
                    elif cardinality is const.Cardinality.UNARY_STREAM:
                        method_cls = client.UnaryStreamMethod
                    elif cardinality is const.Cardinality.STREAM_UNARY:
                        method_cls = client.StreamUnaryMethod
                    elif cardinality is const.Cardinality.STREAM_STREAM:
                        method_cls = client.StreamStreamMethod
                    else:
                        raise TypeError(cardinality)
                    method_cls = cast(type, method_cls)  # FIXME: redundant
                    buf.add('self.{} = {}.{}('.format(name, client.__name__,
                                                      method_cls.__name__))
                    with buf.indent():
                        buf.add('channel,')
                        buf.add('{!r},'.format(full_name))
                        buf.add('{},', request_type)

def __mapping__(self) -> typing.Dict[str, grpclib.const.Handler]:
        return {
            '/grpc.reflection.v1.ServerReflection/ServerReflectionInfo': grpclib.const.Handler(
                self.ServerReflectionInfo,
                grpclib.const.Cardinality.STREAM_STREAM,
                grpclib.reflection.v1.reflection_pb2.ServerReflectionRequest,
                grpclib.reflection.v1.reflection_pb2.ServerReflectionResponse,
            ),