How to extend the core scrubber.js plugin

myScrubber.js

mw.kalturaPluginWrapper(function(){
  // I'm using PluginManager to get the class of the core scrubber plugin in order to extend it
	mw.PluginManager.add( 'myScrubber', mw.PluginManager.getClass('scrubber').extend({
	  // I'm overriding only the updatePlayheadUI method
		updatePlayheadUI: function(val) {
		  
		  // Optionally calling the original method
			// this._super(val);
			
			// Adding my own functionality
			console.log('New playhead position', val);
		}
	}));

});