The collection does not exist in the manager

Am creating a multimodule application and I get the following error on the view;

The collection does not exist in the manager

In the view index file head tags I have the following;

    {{ assets.outputCss('css') }}

In the module class

     $di->setShared('assets', 'Phalcon\Assets\Manager');
       $di['assets']->collection('css')
       ->addCss('css/style.css');

Please advice. I tried initializing in the base controller but the error was the same.