cdm/src/main/java/ucar/nc2/units/DateType.java
public boolean after(Date d) {
    if (isPresent()) return true;
    return date.isAfter(CalendarDate.of(d));
  }
public boolean after(Date d) {
    if (isPresent()) return true;
    return date.isAfter(CalendarDate.of(d));
  }
Is this date after the given date. if isPresent, always true.

@param d test against this date
@return true if this date after the given date