how do you get this error "The controller must return a response (Array(form => Object(Symfony\Component\Form\FormView), departement => Object(MyApp\HomeBundle\Entity\Departement)) given)."?

[dawwwla]

Hello, I added the parameter {id} has my router as follows to add another level in my department:
Former route:
level_ajouter:
pattern: /level/ajouter/
defaults: { _controller: HomeBundle:Level:editer }

New route:
pattern: /level/ajouter/{id}
defaults: { _controller: HomeBundle:Level:editer }

so I recue this error:
The controller must return a response (Array(form => Object(Symfony\Component\Form\FormView), departement => Object(MyApp\HomeBundle\Entity\Departement)) given).