code: function announceClosed(opts) {
        var mdSelect = opts.selectCtrl;
        if (mdSelect) {
          var menuController = opts.selectEl.controller('mdSelectMenu');
          mdSelect.setLabelText(menuController ? menuController.selectedLabels() : '');
          mdSelect.triggerClose();
        }
      }
docs: To notify listeners that the Select menu has closed,
  trigger the [optional] user-defined expression