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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 close(self):
 """Close the KafkaAdminClient connection to the Kafka broker."""

        if not hasattr(self, '_closed') or self._closed:
            log.info("KafkaAdminClient already closed.")
            return

        self._metrics.close()
        self._client.close()
        self._closed = True
        log.debug("KafkaAdminClient is now closed.")