Code from Last Stage won't run in Playground

I've downloaded the code from the last exercise (included at the end of this question) but when I try to run it in the playground I get the following error:

Communication with the playground service was interrupted unexpectedly

Here's the code I'm using:

import UIKit

class Product { let title: String var price: Double = 0.0

init(title: String, price: Double) {
    self.title = title
    self.price = price
}

func discountedPrice(percentage: Double) -> Double {
    return price - (price * percentage / 100)
}

}

enum Size { case Small, Medium, Large init() { self = .Small } }

class Clothing: Product { var size = Size() let designer: String

init (title: String, price: Double, designer: String) {
    self.designer = designer
    super.init(title: title, price: price)
}

convenience init (title: String) {
    self.init(title:title,price:99,designer:"Calvin Klein")
}

override func discountedPrice(_ percentage: Double = 10.0) -> Double {
    return super.discountedPrice(percentage)
}

}

var tshirt = Clothing(title: "Vintage") tshirt.title tshirt.price tshirt.designer tshirt.discountedPrice(50) tshirt.size

let quadcopter = Product(title: "Quadcopter", price: 499.99)