jQuery - Extend addClass to accept callback function

// Extend jQuery addClass function to accept callback function
var oAddClass = $.fn.addClass;
$.fn.addClass = function () {
    for (var i in arguments) {
        var arg = arguments[i];
        if ( !! (arg && arg.constructor && arg.call && arg.apply)) {
            arg();
            delete arg;
        }
    }
    return oAddClass.apply(this, arguments);
}

// Example Usage
//         $('.steps li:not(:last)').addClass('complete', function(e){
//            console.log(e);
 //       });
        

great! but why does not accept the $(this) parameter in the function?