code: function(parent) {
          parent = $(parent);
          parent.removeClass('is-open');
          parent.children(this.ns('menu'))
              .removeAttr('style')
              .aria({
                  expanded: false,
                  hidden: false
              })
              .conceal();
  
          this.fireEvent('hideChild', [parent]);
      }
docs: Event handler to hide the child menu after exiting parent li.
  
  @private
  @param {jQuery} parent