How to get all orders with certain current state in Prestashop? (Symfony Entity Manager)

[Nameofmodulefrontcontrollerfile].php

<?php

use PrestaShop\PrestaShop\Adapter\ServiceLocator;

class [Nameofyourmodule][Nameofmodulefrontcontrollerfile]ModuleFrontController extends ModuleFrontController
{
    private $entityManager;

    public function __construct()
    {
        parent::__construct();
        $this->entityManager = ServiceLocator::get('\\PrestaShop\\PrestaShop\\Core\\Foundation\\Database\\EntityManager');
    }

    public function initContent()
    {
        parent::initContent();                          

        $id_order_state = 5;

        $orders = $this->entityManager->getRepository('Order')
            ->findBy([
                'current_state' => $id_order_state
            ]);

        echo '<pre>'; print_r($orders); echo '</pre>'; die;
    }
}

SymfonyContainer::getInstance()->get()