code: function Plugin(option) {
      return this.each(function () {
        var $this = $(this);
        var data  = $this.data(DataKey);
  
        if (!data) {
          var options = $.extend({}, Default, $this.data(), typeof option == 'object' && option);
          $this.data(DataKey, new Tree($this, options));
        }
      });
    }
docs: Plugin Definition =================