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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 next(self):
 """Get the next batch of messages from the previously fetched messages. If there's no more messages, check if we should auto-delete the messages and raise StopIteration. """

        if not self._messages:
            if self.auto_delete:
                self.delete_messages()
            raise StopIteration

        message = self._messages.pop(0)
        self._processed_messages.append(message)
        return json.loads(message.payload)