public List<Employee> getWorkingEmployees(Date begin, Date end) { Unit unit = this.getUnit();
public List<Employee> getWorkingEmployees(Date begin, Date end) {  Unit departmentUnit = this.getUnit();
    public List<Employee> getWorkingEmployees(Date begin, Date end) {        Unit unit = this.getUnit();        Set<Employee> employees = new HashSet<Employee>();        if (unit != null) {            for (Contract contract : unit.getWorkingContracts(begin, end)) {                employees.add(contract.getEmployee());            }            for (Unit subUnit : unit.getSubUnits()) {                for (Contract contract : subUnit.getWorkingContracts(begin, end)) {                    employees.add(contract.getEmployee());                }            }        }        return new ArrayList<Employee>(employees);    }