@interface UMONItemBuilder : NSObject
@property (strong, nonatomic) NSString *productId;
@property (nonatomic) double quantity;
@property (strong, nonatomic) NSString *type;
@end

@interface UMONItem : NSObject
+ (instancetype)build: (void (^)(UMONItemBuilder *))buildBlock;

- (instancetype)initWithBuilder: (UMONItemBuilder *)builder;

@property (nonatomic, strong, readonly) NSString *productId;
@property (nonatomic, readonly) double quantity;
@property (nonatomic, strong, readonly) NSString *type;
@end