code: public PrettyTime withLastListSeparator(String separator) {
  
          if (separator.equals(this.endListSeparator)) { // includes NPE-check
              return this;
          }
  
          return new PrettyTime(
              this.locale,
              this.refClock,
              this.zeroDigit,
              this.minusSign,
              this.emptyUnit,
              this.weekToDays,
              this.shortStyle,
              this.stdListSeparator,
              separator);
  
      }
docs: /*[deutsch]
  <p>Legt die Listentrennzeichen an der letzten Position fest. </p>
  
  <p><strong>Wichtig:</strong> Die Standardlistentrennzeichen m&uuml;ssen angegeben
  werden, damit diese Methode Wirkung zeigt. </p>
  
  @param   separator   the separator characters between the last two duration items
  @return  changed copy of this instance
  @see     #withDefaultListSeparator(String)
  @since   5.2