code: function(type, listener, useCapture) {
  			if (!this._eventTypes) { this._eventTypes = {}; }
  			var state = this._eventTypes[type];
  			if (!state) {
  				state = this._eventTypes[type] = {level: 0, listeners: []};
  			}
  			var listeners = state.listeners;
  			listeners.push({listener: listener, useCapture: useCapture});
  		}
docs: Adds an event listener to this event target.
  
  @param {String} type The event type.
  @param {Function|EventListener} listener The function or the EventListener that will be executed when the event happens.
  @param {Boolean} [useCapture=false] <code>true</code> if the listener should be trigged in the capture phase.
  
  @see orion.editor.EventTarget#removeEventListener