通过工厂方法调用服务

Right now I can call services from controllers in the following way:

$this -> get('myservice') -> doSomething();

But I want to do this according to the factory method pattern, like this:

ServiceFactory :: createMyservice() -> doSomething();

The problem is that I can't pass parameters with the second method, they're null.

services.yml:

parameters:

services:
    myservice:
        class: AppBundle\Service\Myservice
        factory: [Appbundle\Factory\ServiceFactory, createMyservice]
        arguments:
            - "%kernel.root_dir%"

ServiceFactory.php:

<?php

namespace AppBundle\Factory;

use AppBundle\Service\MyService;

class ServiceFactory
{

    public static function createMyservice($rootDir)
    {
        var_dump($rootDir); // NULL
        $object = new Myservice($rootDir);
        return $object;
    }

}

What's wrong?