code: public void print(
          TimeSpan<? super U> duration,
          Appendable buffer
      ) throws IOException {
  
          for (FormatItem<U> item : this.items) {
              if (item == OrItem.INSTANCE) {
                  break;
              }
              item.print(duration, buffer);
          }
  
      }
docs: /*[deutsch]
  <p>Erzeugt eine textuelle Ausgabe der angegebenen Dauer und
  schreibt sie in den Puffer. </p>
  
  @param   duration	duration object
  @param   buffer      I/O-buffer where the result is written to
  @throws	IllegalArgumentException if some aspects of duration
  prevents printing (for example too many nanoseconds)
  @throws  IOException if writing into buffer fails