code: function (nodes) {//*//
      nodes.data("collapse", true);
      var roots = elementUtilities.getTopMostNodes(nodes);
      for (var i = 0; i < roots.length; i++) {
        var root = roots[i];
        
        // Collapse the nodes in bottom up order
        this.collapseBottomUp(root);
      }
      
      return nodes;
    }
docs: /*
  A helper function to collapse given nodes in a simple way (Without performing layout afterward)
  It collapses all root nodes bottom up.