code: private boolean add(Map<TypeElement, SortedSet<TypeElement>> map, TypeElement superclass, TypeElement typeElement) {
          SortedSet<TypeElement> sset = map.computeIfAbsent(superclass, s ->  new TreeSet<>(comparator));
          if (sset.contains(typeElement)) {
              return false;
          } else {
              sset.add(typeElement);
          }
          return true;
      }
docs: Adjust the Class Tree. Add the class interface  in to it's super classes
  or super interface's sub-interface set.
  
  @param map the entire map.
  @param superclass java.lang.Object or the super-interface.
  @param typeElement sub-interface to be mapped.
  @returns boolean true if class added, false if class already processed.