dojo.declare: unknown base class - dojo.Stateful

So I'm learning Dojo and seeing what I can do with it - I do apologise if this is a stupid question but I can't find a solution.

My code:

    dojo.require("dojo.Stateful");
    dojo.declare('W.Model',dojo.Stateful,{
        foo:'bar'
    });

The error:

Uncaught Error: declare W.Model: unknown base class. Did you use dojo.require to pull it in?

I did use dojo.require to pull it in. What am I missing?

Edit - console.log(dojo.Stateful); returns unde开发者_JAVA百科fined. I am using Google to hot Dojo for me - here: <script src="http://ajax.googleapis.com/ajax/libs/dojo/1.6.0/dojo/dojo.xd.js"></script>

Other classes are loading fine, just dojo.Stateful is a problem.

Do you have the full class declaration in a separate file? Or is this all inline on a page?

If you are doing it inline, wrapping the class until the page has loaded will fix the problem:

dojo.require("dojo.Stateful");
dojo.ready(function() {
    var x = new dojo.Stateful();
    console.log(x);
    dojo.declare('some.class', dojo.Stateful, {
        'x':'y'
    });
});