/**
  * {@inheritDoc}
  *
  * @see
  *     org.eclipse.emf.ecp.edit.spi.ReferenceService#addExistingModelElements(org.eclipse.emf.ecore.EObject,
  *     org.eclipse.emf.ecore.EReference)
  */
 @Override
 public void addExistingModelElements(EObject eObject, EReference eReference) {
   if (delegate == null) {
     return;
   }
   delegate.addExistingModelElements(eObject, eReference);
 }