code: @Override
      public boolean hasNext() {
          boolean has = true;
  
          for (val i: iterators)
              if (!i.hasNext()) {
                  has = false;
                  break;
              }
  
          return has;
      }
docs: Returns {@code true} if the iteration has more elements.
  (In other words, returns {@code true} if {@link #next} would
  return an element rather than throwing an exception.)
  
  @return {@code true} if the iteration has more elements