gistfile1.m

+ (NSManagedObject *)managedObjectFromStructure:(NSDictionary *)structureDictionary 
                                     entityName:(NSString *)entityName 
                       withManagedObjectContext:(NSManagedObjectContext *)context {
    
    NSMutableDictionary *mutableStructureDictionary = [structureDictionary mutableCopy];
    
    NSManagedObject *managedObject = [NSEntityDescription insertNewObjectForEntityForName:entityName 
                                                                   inManagedObjectContext:context];
    
    NSDictionary *relationshipsByName = [[managedObject entity] relationshipsByName];
    
    for (NSString *relationshipName in [relationshipsByName allKeys]) {
        NSRelationshipDescription *relationshipDescription = [relationshipsByName objectForKey:relationshipName];
        NSString *relationshipEntityName = [[relationshipDescription destinationEntity] name];
        
        if (![relationshipDescription isToMany]) {
            NSDictionary *childStructureDictionary = [mutableStructureDictionary objectForKey:relationshipName];
            NSManagedObject *childObject = [[self class] managedObjectFromStructure:childStructureDictionary 
                                                                         entityName:relationshipEntityName 
                                                           withManagedObjectContext:context];
            [managedObject setValue:childObject forKey:relationshipName];
        } else {
            NSMutableSet *relationshipSet = [managedObject mutableSetValueForKey:relationshipName];
            NSArray *relationshipArray = [mutableStructureDictionary objectForKey:relationshipName];
            
            for (NSDictionary *childStructureDictionary in relationshipArray) {
                NSManagedObject *childObject = [[self class] managedObjectFromStructure:childStructureDictionary 
                                                                             entityName:relationshipEntityName 
                                                               withManagedObjectContext:context];
                [relationshipSet addObject:childObject];
            }
        }
        
        [mutableStructureDictionary removeObjectForKey:relationshipName];
    }
    
    [managedObject setValuesForKeysWithDictionary:mutableStructureDictionary];
    
    [mutableStructureDictionary release];
    
    return managedObject;
}

ok, I'll review it today.