void updateSourceCard(SpellAbilityStackInstance si) {
set(TrackableProperty.SourceCard, CardView.get(si.getSourceCard()));
}
// special methods for updating card and player properties as needed and returning the new
// collection
Card setCard(Card oldCard, Card newCard, TrackableProperty key) {
if (newCard != oldCard) {
set(key, CardView.get(newCard));
}
return newCard;
}