Can't figure this one out

Hello,

Apparently, I can't complete the next challenge. I don't know why it won't accept my code. When I test it in a playground in X-Code it works just fine.

These are the requirements:

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"

Does anybody know what the problem might be?

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

    let description: String

    // Add your code below

    init(red: Double,green: Double, blue: Double, alpha: Double) {
        self.red = red //86.0
        self.green = green //191.0
        self.blue =  blue //131.0
        self.alpha = alpha // 1.0
        self.description = ("red: \(red),green:\(green),blue:\(blue),alpha:\(alpha)")
    }

}

RGBColor.init(red: 86.0, green: 191.0, blue: 131.0, alpha: 1.0)