'_' does not make sense

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! I'm a machine!")
  }
}

// Enter your code below

class Robot: Machine {

    override init() {
        super.init()
    }

    override func move(_ direction: String) {
        switch direction {
        case "Up":
            location.y+=1
        case "Down":
            location.y-=1
        case "Left":
            location.x-=1
        case "Right":
            location.x+=1
        default:
            break
        }
    }

}