if (point.hasAttributes(fixedPeriodAttribute, DomainConstants.WORKED_ATTRIBUTES)) {
AttributeType workedAttribute = point.getWorkedAttribute(fixedPeriodAttribute); if (workedAttribute != null && findIntervalEndPointByAttribute(workedAttribute) != null) {
    public Duration calculateFixedPeriod(AttributeType fixedPeriodAttribute) {        List<TimePoint> pointList = new ArrayList<TimePoint>();        for (TimePoint point : getTimePoints()) {            // checks if the point is a WORKED in the fixed period            if (point.hasAttributes(fixedPeriodAttribute, DomainConstants.WORKED_ATTRIBUTES)) {                // || point.hasAttributes(fixedPeriodAttribute, AttributeType.BALANCE)) {                pointList.add(point);            }        }        return this.calculateDurationPointList(pointList);    }