How to assign multidimensional array to class as argument?-Collection of common programming errors

If I try to assign a multidimensional array to a class i get this error

            {Widgets->Widget
                    media='videos'
                    filters=Array('a' => 'b', 'c' => 'd')
            }

 "{assign var='X' value = Array('a' => 'b', 'c' => 'd')}" - Unexpected " => ", expected one of: "","" , ")"'

this doesn't work as well
            filters['a']='b'
            filters['c'] = 'd'

is there a way to circumvent this limit? the version of smarty I’m using is the latest.

the documentation isn’t very clear about it: http://www.smarty.net/docs/en/advanced.features.objects.tpl

regards