Creating a Symfony form with a country drop-down

DefaultController.php

<?php

class DefaultController
{
    public function someAction(Request $request)
    {
        $form = $this->createFormBuilder()
            ->add('the_countries', 'country')
            ->getForm();

        $form->handleRequest($request);
    
        if ($form->isValid()) {
            $country = $form['the_countries']->getData();
            // do something with this country
    
            // then eventually redirect
            return $this->redirectToRoute('some_route');
        }

        return $this->render('default/someTemplate.html.twig', array(
            'form' => $form->createView(),
        ));
    }
}

someTemplate.html.twig

{{ form_start(form) }}
    {{ form_row('form.the_countries') }}
    
    <button type="submit">Save Country</button>
{{ form_end(form) }}