docs: @CheckForNull
    public static Date parseEndingDateOrDateTime(@Nullable String stringDate) {
      if (stringDate == null) {
        return null;
      }
  
      Date date = parseDateTimeQuietly(stringDate);
      if (date != null) {
        return date;
      }
  
      date = parseDateQuietly(stringDate);
      checkArgument(date != null, "Date '%s' cannot be parsed as either a date or date+time", stringDate);
  
      return addDays(date, 1);
    }