Ok in the main page, I put this these lines of Swift code. import SwiftUI import PlaygroundSupport struct Preview: View {     var body: some View {         ProgressView()     } } PlaygroundPage.current.setLiveView(Preview()) I then created a secondary page name ProgressView.Swift too learn how to use multiple pages And put this in it import SwiftUI public struct  ProgressView : View {          public var body: some View {         Text("hello")     } } but every time I hit run I get this error message pop up there was a problem in this playground check your code and try again