Symfony\Component\Form\Form::has PHP Method

    public function has($name)
    {
        return isset($this->children[$name]);
    }

 protected function createFilterQuery(Form $form)
 {
     $qb = $this->getProfessionRepository()->createQueryBuilder('p')->select('p', 'pk')->leftJoin('p.professionkind', 'pk');
     if ($form->get('name')->getNormData()) {
         $qb->andWhere('p.name LIKE :name');
         $qb->setParameter('name', '%' . $form->get('name')->getNormData() . '%');
     }
     if ($form->has('sort_field') && $form->get('sort_field')->getNormData()) {
         $qb->orderBy('p.' . $form->get('sort_field')->getNormData(), $form->get('sort_order')->getNormData());
     } else {
         $qb->orderBy('p.id', 'ASC');
     }
     return $qb->getQuery();
 }