[HELP] Understanding createCallback

I'm trying to get my head around createCallback but i'm getting a bit confused with it, i've assumed that it is possible to use createCallback to apply a callback to ANY function you create?

So the following is how i think it works?

Code:

---

function shout(msg){
 Ext.Msg.alert('ALERT!', msg);
}

function run(){
 ds.load();
 ds.on('load', function(){ds.getAt(0)})
}

run().createCallback(shout('I wish i understood this'))

---

Am i correct? or way off the mark?!

Try:

Code:

---

function shout(msg){
 Ext.Msg.alert('ALERT!', msg);
}

function run(fn){
 ds.on('load', fn, null, {single:true});
 ds.load();
}

run(shout.createCallback('I wish i understood this'));

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