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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 terminate_ex(self, nodes, threads=False, attempts=3):
 """Wrapper method for terminate. :param nodes: Nodes to be destroyed. :type nodes: ``list`` :param attempts: The amount of attempts for retrying to terminate failed instances. :type attempts: ``int`` :param threads: Whether to use the threaded approach or not. :type threads: ``bool`` """

        while nodes and attempts > 0:
            if threads:
                nodes = self.terminate_with_threads(nodes)
            else:
                nodes = self.terminate(nodes)
            if nodes:
                logger.info("Attempt to terminate the remaining instances once more.")
                attempts -= 1
        return nodes