findItems = (aItemItems) => {
				aItemItems.forEach((oItem) => {
					if (!this._isMenuItemGroup(oItem)) {
						aItems.push(oItem);
					} else {
						findItems(oItem.getItems());
					}
				});
			}
Returns list of items stored in <code>items</code> aggregation. If there are group items,
the items of the group are returned instead of their group item.

@returns {sap.m.MenuItem} List of all menu items
@private