docs: public static String getTimeRangeString(Date fromDate, Date toDate) {
          if (fromDate == null && toDate == null) {
              return null;
          }
  
          StringBuilder sbr = new StringBuilder();
          if (fromDate != null) {
              sbr.append(format(fromDate));
          }
          sbr.append(",");
          if (toDate != null) {
              sbr.append(format(toDate));
          }
          return sbr.toString();
      }