'Expects to find \'<address addr="127.0.0.1" addrtype="ipv6"/>\'
in the node
@return ip_address or \'unknown\''

def get_ipv6_address(self):

    ip_address = self.get_attrib_from_subnode("address[@addrtype='ipv6']", 'addr')
    return (ip_address if ip_address else 'unknown')
