final ListIterator it = parents.listIterator( parents.size() );
it.previous();
final Object parent = it.previous();
if ( parent instanceof ConditionalElementDescr ) {
final ConditionalElementDescr parentDescr = (ConditionalElementDescr) parent;
parentDescr.addDescr( orDescr );
} else if ( parent instanceof PatternDescr ) {
final PatternDescr parentDescr = (PatternDescr) parent;
parentDescr.addConstraint( orDescr );
}
return null;
}