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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 remove_host(self, host):
 """ Called when the control connection observes that a node has left the ring. Intended for internal use only. """

        if host and self.metadata.remove_host(host):
            log.info("Cassandra host %s removed", host)
            self.on_remove(host)