private void GetOperationRooms(List <ProcedureEntity> list, ref Procedure procedure)
        {
            // get the list of all the operation.
            List <Operation> operationList = GetOperationsList(list, procedure);
            // get the unique list of operation room.
            var opRoomsName = operationList.Select(o => o.ORName).Distinct();

            // create operation room object with the each
            foreach (string opRoomName in opRoomsName)
            {
                OperationRoom operationRoom = new OperationRoom();
                operationRoom.Name = opRoomName;
                // get all the operations from from opRoomName
                var opList = from op in operationList
                             where op.ORName == opRoomName
                             select op;
                // add the list of operation to the operation room.
                operationRoom.Add(opList);
                // add the operation room to the procedure object.
                procedure.AddOperationRoom(operationRoom);
            }
        }