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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 _waitForIP(cls, instance):
 """ Wait until the instances has a public IP address assigned to it. :type instance: boto.ec2.instance.Instance """

        logger.debug('Waiting for ip...')
        while True:
            time.sleep(a_short_time)
            instance.update()
            if instance.ip_address or instance.public_dns_name or instance.private_ip_address:
                logger.debug('...got ip')
                break