iRule or LTM Policy to pre-fix desired www. sites

I like that and thats similar to what I was trying to come up with prior posting on here. Also to be clear, the inner if statement doesn't need an else. It if doesn't match any constraints it will just leave that inner if statement and continue on in the outter if statement, right?

when HTTP_REQUEST {
  if { [class match [HTTP::host] equals Datagroup1] } {
    if { !([HTTP::host] starts_with "www.") && !([class lookup [HTTP::host] Datagroup1] equals "strict") } {
      HTTP::redirect "https://www.[HTTP::host][HTTP::uri]"
    }
    pool prod_sites
  } else {
  HTTP::respond 403
  }
}