php - Eloquent sortBy - Specify asc or desc -

trying sort eloquent collection:

$collection->sortby('field'); 

there no information in laravel 4's docs on how choose descending or ascending sort method.

is possible?

http://laravel.com/api/4.1/illuminate/database/eloquent/collection.html#method_sortby

$collection->sortby('field', [], true);//true descending