Clearing cookies for site with iRule

I found another article which suggests I may need something more like this. What I am struggling with is how to check of the cookie_version2 cookie exists so we don't repeatedly expire all cookies. Any suggestions on how I can do that?

when HTTP_REQUEST { 
    set request_cookies [HTTP::cookie names] 
}

when HTTP_RESPONSE {
    foreach a_cookie $request_cookies { 
        log local0. "Remove cookie: $a_cookie" 
        HTTP::header insert Set-Cookie "$a_cookie=deleted;expires=Thu, 01-Jan-1970 00:00:10 GMT;path=/" 
    } 
 
    log local0. "Add cookie cookie_version=1 to track if the cookies have been cleared before or not"
    HTTP::cookie insert name "cookie_version2" value "1" path "/"
    HTTP::cookie attribute cookie_version2 value "expires" "Thu, 09-April-2022 00:00:00 GMT"

    #log local0. "Add dummy cookie to see if cookie deletions is working"
    #HTTP::cookie insert name "dummy_cookie" value "1"  path "/"
    #HTTP::cookie attribute dummy_cookie value "expires" "Thu, 09-April-2022 00:00:00 GMT"
}