docs: public void setSkipHours(final List<Integer> skipHours) {
          if (skipHours != null) {
              for (int i = 0; i < skipHours.size(); i++) {
                  final Integer iHour = skipHours.get(i);
                  if (iHour != null) {
                      final int hour = iHour.intValue();
                      if (hour < 0 || hour > 24) {
                          throw new IllegalArgumentException("Invalid hour [" + hour + "]");
                      }
                  } else {
                      throw new IllegalArgumentException("Invalid hour [null]");
                  }
              }
          }
          this.skipHours = skipHours;
      }