Is this code challenge crashing every time you "check your work"?

class Point {
    var x: Int
    var y: Int

    init(x: Int, y: Int){
        self.x = x
        self.y = y
    }
}


class Machine {
    var location: Point

    init() {
        self.location = Point(x: 0, y: 0)
    }

    func move(direction: String) {
        print("Do nothing! Im a machine!")
    }
}

class Robot: Machine {
    override init(){
        super.init(){
            self.location = Point(x: 0, y: 0)
        }
    }
    override func move(direction: String){
        let directions = ["Up", "Down", "Right", "Left"]
        for directions in directions{
            switch direction {
            case "Up": Robot.y += 1
            case "Down": Robot.y -= 1
            case "Left": Robot.x -= 1
            case "Right": Robot.x += 1
            default: break
            }
        }
}
}