docs: @Override
      public int compareTo(final DisabledDuration o) {
          int result = start.compareTo(o.getStart());
          if (result == 0) {
              if (end == null && o.getEnd() == null) {
                  result = 0;
              } else if (end != null && o.getEnd() != null) {
                  result = end.compareTo(o.getEnd());
              } else if (o.getEnd() == null) {
                  return -1;
              } else {
                  return 1;
              }
          }
          return result;
      }