Error PHP que no comprendo

[NaRanJiTo78]

darkasecas, entonces que tengo que hacer, definir "$form"?

Aqui es donde lo tengo que definir?

Código PHP:

function verifyFormToken($form) {
        
        // check if a session is started and a token is transmitted, if not return an error
        if(!isset($_SESSION[$form.'_token'])) { 
            return false;
        }
        
        // check if the form is sent with token in it
        if(!isset($_POST['token'])) {
            return false;
        }
        
        // compare the tokens against each other if they are still the same
        if ($_SESSION[$form.'_token'] !== $_POST['token']) {
            return false;
        }
        
        return true;
    }
    
    function generateFormToken($form) {
    
        // generate a token from an unique value, took from microtime, you can also use salt-values, other crypting methods...
        $token = md5(uniqid(microtime(), true));  
        
        // Write the generated token to the session variable to check it against the hidden field when the form is sent
        $_SESSION[$form.'_token'] = $token; 
        
        return $token;
    }
 

Esque ya digo que no entiendo mucho de PHP...

Un saludo, gracias!