cdm/src/main/java/ucar/nc2/time/CalendarDateRange.java
static public CalendarDateRange of(DateRange dr) {
    if (dr == null) return null;
    return CalendarDateRange.of( dr.getStart().getDate(), dr.getEnd().getDate());
  }
static public CalendarDateRange of(DateRange dr) {
    if (dr == null) return null;
    return CalendarDateRange.of( dr.getStart().getDate(), dr.getEnd().getDate());
  }
Does not handle non-standard calendars
@deprecated