code: function (nodes, options) {
      // If there is just one node to expand we need to animate for fisheye view, but if there are more then one node we do not
      if (nodes.length === 1) {
        
        var node = nodes[0];
        if (node._private.data.collapsedChildren != null) {
          // Expand the given node the third parameter indicates that the node is simple which ensures that fisheye parameter will be considered
          this.expandNode(node, options.fisheye, true, options.animate, options.layoutBy);
        }
      } 
      else {
        // First expand given nodes and then perform layout according to the layoutBy parameter
        this.simpleExpandGivenNodes(nodes, options.fisheye);
        this.endOperation(options.layoutBy);
      }
  
      /*
       * return the nodes to undo the operation
       */
      return nodes;
    }
docs: Expand the given nodes perform end operation after expandation