How to extract autonomous_system_number from GeoIPISP.dat in an iRule

We are trying to create an iRule to redirect an LTM HTTP request based on AS number/autonomous_system_number. I tried using the "whereis" function but it does not have AS Number as an option just the ISP. According to Maxmind GeoIPISP.dat file includes the AS number. Is there a way extract AS Number besides using "whereis"?

when CLIENT_ACCEPTED {
log local0. "client IP address for connection is: [IP::client_addr] [whereis [IP::client_addr] isp]"
}