Custom Initialisers Code Challenge (Object Orientated Swift)

My code compiles with wifi v3 and Xcode v8 in the Playground, but not on the website:

struct RGBColor {
    let red: Double
    let green: Double
    let blue: Double
    let alpha: Double

    let description: String

    // Add your code below

    init() {
        self.red = 86.0
        self.green = 191.0
        self.blue = 131.0
        self.alpha = 1.0

        self.description = "red: \(red), green: \(green), blue: \(blue), alpha: \(alpha)"
    }

}



let colourTable = RGBColor.init()

colourTable.description

I would like confirmation if I have completed the challenge as demanded:

In the editor, I’ve declared a struct named RGBColor that models a color object in the RGB space.

Your task is to write a custom initializer method for the object. Using the initializer assign values to the first four properties. Using the values assigned to those properties create a value for the description property that is a string representation of the color object.

For example, given the values 86.0 for red, 191.0 for green, 131.0 for blue and 1.0 for alpha, each of the stored properties should hold these values and the description property should look like this:

"red: 86.0, green: 191.0, blue: 131.0, alpha: 1.0"

ref: https://teamtreehouse.com/library/objectoriented-swift-2/complex-data-structures/custom-initializers

Thanks!