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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 send_message(self, *args, **kwargs):
 """ Sends a message in the context of this conversation. Shorthand for `telethon.client.messages.MessageMethods.send_message` with ``entity`` already set. """

        message = await self._client.send_message(
            self._input_chat, *args, **kwargs)

        self._outgoing.add(message.id)
        self._last_outgoing = message.id
        return message