Unexpected "stylesheets" tag

Testing Symfony 3 I get this error when I follow this example:

http://symfony.com/doc/current/cookbook/assetic/asset_management.html#cookbook-assetic-including-css

Code:

```
{% stylesheets 'css/*' filter='cssrewrite' %}
<link rel="stylesheet" href="{{ asset_url }}" />
{% endstylesheets %}
```

Error:

```
Unknown "stylesheets" tag in ::base.html.twig at line 14
```
