Dojo dijit.layout.TabContainer - how to add class to tab?

http://stackoverflow.com/questions/10636360/dojo-dijit-layout-tabcontainer-how-to-add-class-to-tab

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/dojo/1.7.2/dijit/themes/claro/claro.css">
<style type="text/css">
    #tabs {
        width: 200px;
        height: 200px;
    }
    
    .myTabClass .tabLabel {
      color: blue !important;
    }
    
</style>
<div id="tabs" dojoType="dijit.layout.TabContainer">
  <div id="123" dojoType="dijit.layout.ContentPane" title="test123">
    123
  </div>
  <div id="456" dojoType="dijit.layout.ContentPane" title="test456">
    456
  </div>
</div>

JavaScript

dojo.require("dojo.parser");
dojo.require("dijit.layout.TabContainer");
dojo.require("dijit.layout.ContentPane");

dojo.ready(function(){
  
  dojo.parser.parse();
      
  var tabContainer = dijit.byId("tabs"); 
  dojo.addClass(tabContainer.tablist.pane2button["1238"].domNode, "myTabClass");
  
});