Modifing an model element

Hello everyone,
Following this tutorial, it, I tried to make a very simple service that can edit a property value of an Physical component.
Based on the example, I wrote this code as a buisiness rule :
public void run(ModelAccessor properties, Object[] selection) {
for (final Object object : selection){
ExecutionManager manager = TransactionHelper.getExecutionManager(object).execute(new AbstractReadWriteCommand() {
public void run() {
if (object instanceof PhysicalComponent) {
// traitement du PVMT
PhysicalComponent PC = (PhysicalComponent) object;
PropertyValueGroup PV = PC.getAppliedPropertyValueGroups().get(0);
IntegerPropertyValue IntPV = (IntegerPropertyValue) PV.getOwnedPropertyValues().get(0);
IntegerPropertyValue IntPVModifie = (IntegerPropertyValue) PV.getOwnedPropertyValues().get(0);

However, the reference to ‘TransactionHelper’ cannot be treated by Capella Studio.
Is this tutorial still correct ? I don’t know whether they are updated or not, and maybe the way to edit element is not the same from the version 1.