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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 _get(self, *args, **kwargs):
 """ Gets a single list of messages from all storage backends. """

        all_messages = []
        for storage in self.storages:
            messages, all_retrieved = storage._get()
            # If the backend hasn't been used, no more retrieval is necessary.
            if messages is None:
                break
            if messages:
                self._used_storages.add(storage)
            all_messages.extend(messages)
            # If this storage class contained all the messages, no further
            # retrieval is necessary
            if all_retrieved:
                break
        return all_messages, all_retrieved