issue with cookie persist irule

when HTTP_REQUEST {
         If the cookie exists, connect to the IP specified in the cookie
        if { [HTTP::cookie exists "cookie"] } {
                if { ([HTTP::cookie "cookie"] ne "") } {
                        set persist_node [HTTP::cookie "cookie"]
                       log local0. "persist_node is $persist_node and server pool is [LB::server pool]"
                       set current_pool [LB::server pool]
                        foreach member [active_members -list $current_pool] {
                                set node [lindex $member 0]
                                if { $node eq $persist_node } {
                                        node $persist_node [lindex $member 1]
                                }
                        }
                }
        }
}