Dojox charting programmatically using store series

I have been trying to get dojo charting working using the programmatic method. I have tried the following but the graph is not showing.

//Requirements

dojo.require("dojo.data.ItemFileWriteStore");
dojo.require('dojox.charting.Chart2D');
dojo.require('dojox.charting.widget.Chart2D');
dojo.require('dojox.charting.themes.PlotKit.blue');
dojo.require('dojox.charting.plot2d.Columns');
dojo.require('dojox.charting.StoreSeries');

dojo.ready(function() {


var data = {"identifier":"MyMonth","label":"MyMonth","items":[{"MyAmount":"98498.67","MyMonth":"1"},{"MyAmount":"114384.10","MyMonth":"2"},{"MyAmount":"125307.86","MyMonth":"3"},{"MyAmount":"87534.38","MyMonth":"4"},{"MyAmount":"90376.60","MyMonth":"5"},{"MyAmount":"96233.60","MyMonth":"6"},{"MyAmount":"112824.29","MyMonth":"7"},{"MyAmount":"119593.06","MyMonth":"8"},{"MyAmount":"95691.64","MyMonth":"9"}]};

var mystore= new dojo.data.ItemFileWriteStore({data: data});

var chart1 = new dojox.charting.Chart2D('testChart').
    setTheme(dojox.charting.themes.PlotKit.blue).
    addAxis('x', {min: 0, max: 12}).
    addAxis('y', { vertical: true, min: 1}).
    addPlot('default', {type: 'Columns'}). 
    addSeries("My Month", new dojox.charting.StoreSeries(mystore, {query:{}}, "MyMonth")).
    render();
});

Instead of using dojox.charting.StoreSeries, I used the dojox.charting.DataSeries while using the same code and it worked

addSeries("My Month", new dojox.charting.DataSeries(mystore, {query:{}}, "MyMonth")).

Thats it.