code: public static TimeUnit toTimeUnit(final ChronoUnit tu) {
          if (tu == null) {
              return null;
          }
          switch (tu) {
              case DAYS:
                  return TimeUnit.DAYS;
              case HOURS:
                  return TimeUnit.HOURS;
              case MINUTES:
                  return TimeUnit.MINUTES;
              case SECONDS:
                  return TimeUnit.SECONDS;
              case MICROS:
                  return TimeUnit.MICROSECONDS;
              case MILLIS:
                  return TimeUnit.MILLISECONDS;
              case NANOS:
                  return TimeUnit.NANOSECONDS;
              default:
                  throw new UnsupportedOperationException("Temporal unit is not supported");
          }
      }
docs: To time unit time unit.
  
  @param tu the tu
  @return the time unit