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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 async def publish(self, exchange: str, routing: str, message: Union[str, dict], exchange_type: ExchangeType_ = 'topic'):
 """ Publish a new event message. Connections are created automatically when calling `publish()`, and will attempt to reconnect if connection was lost. For more information on publishing AMQP messages, see https://www.rabbitmq.com/tutorials/tutorial-three-python.html Args: exchange (str):
 The AMQP message exchange to publish the message to. A new exchange will be created if it does not yet exist. routing (str):
 The routing identification with which the message should be published. Subscribers use routing information for fine-grained filtering. Routing can be expressed as a '.'-separated path. message (Union[str, dict]):
 The message body. It will be serialized before transmission. exchange_type (ExchangeType_, optional):
 When publishing to a previously undeclared exchange, it will be created. `exchange_type` defines how the exchange distributes messages between subscribers. The default is 'topic', and acceptable values are: 'topic', 'direct', or 'fanout'. Raises: aioamqp.exceptions.AioamqpException: * Failed to connect to AMQP host * Failed to send message * `exchange` already exists, but has a different `exchange_type` """

        try:
            await self._ensure_channel()
        except Exception:
            # If server has restarted since our last attempt, ensure channel will fail (old connection invalid)
            # Retry once to check whether a new connection can be made
            await self._ensure_channel()

        # json.dumps() also correctly handles strings
        data = json.dumps(message).encode()

        await self._channel.exchange_declare(
            exchange_name=exchange,
            type_name=exchange_type,
            auto_delete=True
        )

        await self._channel.basic_publish(
            payload=data,
            exchange_name=exchange,
            routing_key=routing
        )