syntax error in iRule using data group

in LTM V10.2, I am trying to match against a bunch of IPs included in a datagroup and am getting an error. The datagroup config looks good (see below) and when I remove the $::safeiiplist and insert a single IP, it works.

when HTTP_REQUEST { set username [HTTP::cookie username] log local0. "URI is [string tolower [HTTP::uri]]. Username is $username." if {($username contains "\@jones") || ($username contains "\@smith") } { log local0. "Matched username! Username is $username." if { [IP::addr [IP::client_addr] equals $::safeiiplist] } { log local0. "Matched client address: [IP::client_addr]" switch -glob [HTTP::uri] {

ERROR: bad IP network address format invoked from within "IP::addr [IP::client_addr] equals $::safeiiplist"

Datagroup config: class safeiiplist { host 207.140.60.67 }