public GroupingRequest setTimeZone(TimeZone timeZone) {
        this.timeZone = timeZone;
        return this;
    }
Sets the {@link TimeZone} used when resolving time expressions such as {@link
com.yahoo.search.grouping.request.DayOfMonthFunction} and {@link com.yahoo.search.grouping.request.HourOfDayFunction}.

@param timeZone the time zone to set.
@return this, to allow chaining.
container-search/src/main/java/com/yahoo/search/grouping/GroupingRequest.java