code: public int addAll(Iterable<? extends KTypeCursor<? extends KType>> iterable) {
      int count = 0;
      for (KTypeCursor<? extends KType> cursor : iterable) {
        if (add(cursor.value)) {
          count++;
        }
      }
      return count;
    }
docs: Adds all elements from the given iterable to this set.
  
  @return Returns the number of elements actually added as a result of this
  call (not previously present in the set).