code: public boolean isInRange(@Nullable CalendarDay minDate, @Nullable CalendarDay maxDate) {
      return !(minDate != null && minDate.isAfter(this)) &&
          !(maxDate != null && maxDate.isBefore(this));
    }
docs: Determine if this day is within a specified range
  
  @param minDate the earliest day, may be null
  @param maxDate the latest day, may be null
  @return true if the between (inclusive) the min and max dates.