I'm trying to get values form an array which I declared in parameters.yml

```
# parameters.yml
parameters:
    ...
    objects: {object1: 1, object2: 2, object3: 3}

```

but once I try to get "objects" from that file using this code 

```
$builder->add('list', ChoiceType::class, array ('objects' => $this->container->getParameter('categories') ));

```

I get the following error 

```
Notice: Undefined property: Project\Bundle\Form\EntityType::$container

```

Any suggestions?