code: function(itemOrArray) {
  			var oldSelection = this._selections;
  			if (Array.isArray(itemOrArray)) {	
  				this._selections = itemOrArray.length > 0 ? itemOrArray.slice() : null;
  			} else if (itemOrArray) {
  				this._selections = [itemOrArray];
  			} else {
  				this._selections = null;
  			}
  			if (oldSelection !== this._selections) {
  				this.dispatchEvent({type:"selectionChanged", selection: this._getSingleSelection(), selections: this._selections}); //$NON-NLS-0$
  			}
  		}
docs: Sets the current selection. Dispatches a <code>selectionChanged</code> event.
  @param {Object|Object[]|null} itemOrArray A single selected item, or an array of selected items, or <code>null</code> (meaning no selection).
  @see orion.selection.Selection#event:selectionChanged