code: public static CharSequence getRelativeDateTimeString(Context context, ReadablePartial time,
                                                           ReadablePeriod transitionResolution, int flags) {
          if (!time.isSupported(DateTimeFieldType.hourOfDay())
              || !time.isSupported(DateTimeFieldType.minuteOfHour())) {
              throw new IllegalArgumentException("getRelativeDateTimeString() must be passed a ReadablePartial that " +
                  "supports time, otherwise it makes no sense");
          }
  
          return getRelativeDateTimeString(context, time.toDateTime(DateTime.now()), transitionResolution, flags);
      }
docs: Return string describing the time until/elapsed time since 'time' formatted like
  "[relative time/date], [time]".
  
  See {@link android.text.format.DateUtils#getRelativeDateTimeString} for full docs.
  
  @throws IllegalArgumentException if using a ReadablePartial without a time component
  @see #getRelativeDateTimeString(Context, ReadableInstant, ReadablePeriod, int)