The method below is from a doubly linked list implementation of a list ADT. The doubly linked list uses the project #2 DLLNode class for node objects. It has both head and tail references. New nodes are added to the end of the list. This method creates and returns a string representing the contents of the list, in the reverse order of insertion. What is the missing statement?

public String gnirtSot() { DLLNode currNode = tail; String listString = ""; while (currNode != null) { listString = listString + " " + currNode.getInfo() + " "; missing statement } return listString; }