initialize Form with parameter doesn't work

Hi,

In the documentation of Phalcon

https://docs.phalcon.io/en/latest/reference/forms.html

says I write it correctly but it doesn't work:

$form = new SpecialForm("Foo", "Bar");

class SpecialForm extends Form
{   
    public function initialize($para, $meter)
    {
        print_r("para");
        print_r($para);
        print_r("meter");
        print_r($meter);

it only displays: parameter

please help me!