protected override ImmSortedMap <TKey, TValue> Difference(ImmSortedMap <TKey, TValue> other) { return(Root.SymDifference(other.Root, Lineage.Mutable()).WrapMap(Comparer)); }
protected override ImmSortedSet <T> Difference(ImmSortedSet <T> other) { return(Root.SymDifference(other.Root, Lineage.Mutable()).Wrap(Comparer)); }