code: public final void setTimeZone(final TimeZone timeZone) {
          if (!Value.DATE.equals(type)) {
              for (Date date: this) {
                  ((DateTime) date).setTimeZone(timeZone);
              }
          }
          this.timeZone = timeZone;
          this.utc = false;
      }
docs: Applies the specified timezone to all dates in the list.
  All dates added to this list will also have this timezone
  applied.
  @param timeZone a timezone to apply to contained dates