async def get_upstream_dns(cls) -> list:
        """Upstream DNS server addresses.

        Upstream DNS servers used to resolve domains not managed by this MAAS
        (space-separated IP addresses). Only used when MAAS is running its own
        DNS server. This value is used as the value of 'forwarders' in the DNS
        server config.
        """
        data = await cls.get_config("upstream_dns")
        return [] if data is None else re.split(r'[,\s]+', data)
async def get_upstream_dns ( cls ) -> list : data = await cls . get_config ( "upstream_dns" ) return [ ] if data is None else re . split ( r'[,\s]+' , data )
Upstream DNS server addresses.

        Upstream DNS servers used to resolve domains not managed by this MAAS
        (space-separated IP addresses). Only used when MAAS is running its own
        DNS server. This value is used as the value of 'forwarders' in the DNS
        server config.