docs: public int compareTo(BaseSingleFieldPeriod other) {
          if (other.getClass() != getClass()) {
              throw new ClassCastException(getClass() + " cannot be compared to " + other.getClass());
          }
          int otherValue = other.getValue();
          int thisValue = getValue();
          if (thisValue > otherValue) {
              return 1;
          }
          if (thisValue < otherValue) {
              return -1;
          }
          return 0;
      }