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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:
 def send_message(self, messages, close_on_done=False):
 """Send a single message or batched message. :param messages: A message to send. This can either be a single instance of `Message`, or multiple messages wrapped in an instance of `BatchMessage`. :type message: ~uamqp.message.Message :param close_on_done: Close the client once the message is sent. Default is `False`. :type close_on_done: bool :raises: ~uamqp.errors.MessageException if message fails to send after retry policy is exhausted. """

        batch = messages.gather()
        pending_batch = []
        for message in batch:
            message.idle_time = self._counter.get_current_ms()
            self._pending_messages.append(message)
            pending_batch.append(message)
        self.open()
        running = True
        try:
            while running and any([m for m in pending_batch if m.state not in constants.DONE_STATES]):
                running = self.do_work()
            failed = [m for m in pending_batch if m.state == constants.MessageState.SendFailed]
            if any(failed):
                details = {"total_messages": len(pending_batch), "number_failed": len(failed)}
                details['failed_messages'] = {}
                exception = None
                for failed_message in failed:
                    exception = failed_message._response  # pylint: disable=protected-access
                    details['failed_messages'][failed_message] = exception
                raise errors.ClientMessageError(exception, info=details)
        finally:
            if close_on_done or not running:
                self.close()