[exim] lookup syntax help

I'm trying an experiment - but it somplains about the syntax. missing
lookup type

process_and_forward_auto:
driver = manualroute
domains = +preprocess_auto_domains
condition = ${if match{$h_X-Spam:}{HIGH}{no}{yes}}
transport = remote_smtp
route_list = * ${lookup dnsdb{a=mail-in.$domain}{$value}}