docs: public void setDateFormat(Locale locale, boolean isoDateFormat) {
          this.locale = locale;
          if (null == locale) {
              dateFormat = FormatSet.customizeDateFormat(DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.MEDIUM), isoDateFormat);
          } else {
              dateFormat = FormatSet.customizeDateFormat(DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.MEDIUM, locale), isoDateFormat);
          }
      }