code: PropertyFilterList<S> getTailPropertyFilterList() {
          PropertyFilterList<S> tail = mTailPropertyFilterList;
          if (tail == null) {
              buildFilterValues();
              tail = mTailPropertyFilterList;
          }
          return tail;
      }
docs: Returns tail of linked list, and so it can only be traversed by getting
  previous nodes.
  
  @return tail of PropertyFilterList, or null if no parameters