gistfile1.m

- (void)saveModel:(MTLModel *)model forKey:(NSString *)key error:(NSError *__autoreleasing *)error
{
    NSFileManager *fileManager  = [NSFileManager defaultManager];
    NSString *path              = [self pathForModel:model];
    path                        = [path stringByAppendingPathComponent:key];
    
    
}

- (MTLModel *)objectForKey:(NSString *)key
{
    return nil;
}