public EmployeePlanningWorkingModelHelper(IEmployeePlanningWorkingModelService service)
        {
            if (service == null)
                throw new ArgumentNullException();

            _service = (service as EmployeePlanningWorkingModelService);

            if (_service == null)
                throw new ArgumentNullException();
        }
        public EmployeePlanningWorkingModelHelper(IEmployeePlanningWorkingModelService service)
        {
            if (service == null)
                throw new ArgumentNullException();

            _service = (service as EmployeePlanningWorkingModelService);

            if (_service == null)
                throw new ArgumentNullException();
        }