Need help to convert Rules from BIG-IP v4 to v9

when HTTP_REQUEST {
  if { [matchclass [string tolower [HTTP::uri]] contains $::cluster1_class] or
       [HTTP::cookie exists "BIGipServercluster1_Pool"] } {
    pool cluster1_pool
  } elseif { [matchclass [string tolower [HTTP::uri]] contains $::cluster3_class] or
       [HTTP::cookie exists "BIGipServercluster3_Pool"] } {
    pool cluster3_Pool
  } else {
    pool AllClusters
  }
}