code: public LocalTime minusHours(int hours) {
          if (hours == 0) {
              return this;
          }
          long instant = getChronology().hours().subtract(getLocalMillis(), hours);
          return withLocalMillis(instant);
      }
docs: Returns a copy of this time minus the specified number of hours.
  <p>
  This LocalTime instance is immutable and unaffected by this method call.
  <p>
  The following three lines are identical in effect:
  <pre>
  LocalTime subtracted = dt.minusHours(6);
  LocalTime subtracted = dt.minus(Period.hours(6));
  LocalTime subtracted = dt.withFieldAdded(DurationFieldType.hours(), -6);
  </pre>
  
  @param hours  the amount of hours to subtract, may be negative
  @return the new LocalTime minus the increased hours