code incorrect

The example shown for conflict resolution is incorrect.

The box showing the various conflict resolution techniques and sample code -

class LocalWinConflictResolver: ConflictResolver {
func resolve(conflict: Conflict) -> Document? {

class RemoteWinConflictResolver: ConflictResolver {
func resolve(conflict: Conflict) -> Document? {

class MergeConflictResolver: ConflictResolver {
func resolve(conflict: Conflict) -> Document? {

should replace ConflictResolver with ConflictResolverProtocol so for the first example we should see:

class LocalWinConflictResolver: ConflictResolverProtocol {
func resolve(conflict: Conflict) -> Document? {

The remaining ones should also follow this too.