@Override
 protected Collection<? extends EStructuralFeature> getChildrenFeatures(Object object) {
   if (childrenFeatures == null) {
     super.getChildrenFeatures(object);
     childrenFeatures.add(ReqIF10Package.Literals.REQ_IF_CONTENT__SPEC_RELATION_GROUPS);
   }
   return childrenFeatures;
 }