return null;
    public RoleType getPeopleOfAdvisory() throws FenixFilterException, FenixServiceException {        List<RoleType> list = new ArrayList<RoleType>();        List<RoleType> resultList = new ArrayList<RoleType>();        IAdvisory advisory = this.getAdvisory();        for (IPerson person : advisory.getPeople()) {            IRole rolePerson = person.getPersonRole(RoleType.TEACHER);            IRole roleEmployee = person.getPersonRole(RoleType.EMPLOYEE);            IRole roleStudent = person.getPersonRole(RoleType.STUDENT);            if (rolePerson != null) {                list.add(RoleType.TEACHER);            }            if (roleEmployee != null) {                list.add(RoleType.EMPLOYEE);            }            if (roleStudent != null) {                list.add(RoleType.STUDENT);            }            if (!resultList.isEmpty()) {                resultList = (List<RoleType>) CollectionUtils.intersection(resultList, list);            }            else{                resultList.addAll(list);            }            if (resultList.size() == 1) {                return list.get(0);            }            list.clear();        }        return null;    }