I'm trying to extend dojox.collections.SortedList to allow an ascending or descending sort order based on a boolean passed into the constructor. This is my first go at extending a widget, so I'm hitting a few life cycle problems.

My code is :

// SortedList supporting ascending and descending sort
dojo.provide("gwp.SortedListTwoWay");
dojo.require("dojox.collections._base");
dojo.declare("gwp.SortedListTwoWay", dojox.collections.SortedList, {
	sortAsc: true,
	constructor: function(/*object*/dictionary, /*boolean*/ sortAscending)
	{
		this.inherited([dictionary]);
		if (sortAscending) this.sortAsc = sortAscending;
	},
	sorter: function(a,b){
		if (this.sortAsc){
			if (a.key > b.key) return 1;
			if (a.key < b.key) return -1;
			return 0;
		} else {
			if (a.key > b.key) return -1;
			if (a.key < b.key) return 1;
			return 0;
		}
	}
});

With the call to the constructor in my code as

GWPGlobal.personStoreItems = new gwp.SortedListTwoWay(null, false);

And the error that this gives me is :
TypeError: args has no properties message=args has no properties

I think my problem is in the call to this.inherited(), but after a day of head scratching and trying to follow source code, I'm stumped. Any help would be much appreciated.