code: function(node, mode){
  		if(mode === undefined || mode === "over"){
  			mode = "child";
  		}
  		switch(mode){
  		case "after":
  			return this.getParent().addChildren(node, this.getNextSibling());
  		case "before":
  			return this.getParent().addChildren(node, this);
  		case "child":
  		case "over":
  			return this.addChildren(node);
  		}
  		_assert(false, "Invalid mode: " + mode);
  	}
docs: Append or prepend a node, or append a child node.
  
  This a convenience function that calls addChildren()
  
  @param {NodeData} node node definition
  @param {string} [mode=child] 'before', 'after', or 'child' ('over' is a synonym for 'child')
  @returns {FancytreeNode} new node