SwiftUI – PreviewProvider pass nil for optional Void function

struct Toolbar: View {
    
    let closeThisView: () -> Void?
    var toolbarTitle: String
    
    var body: some View {
        
        Text("bla")
    }
}


struct Toolbar_Previews: PreviewProvider {
    
    static var previews: some View {
        Toolbar(closeThisView: nil, toolbarTitle: "comments")
            .preferredColorScheme(.dark)
    }
}

How can I pass nil there or any function since I don’t need it in the preview anyway? Like this is what I’ve also tried:

struct Toolbar_Previews: PreviewProvider {
    
    @Environment(\.dismiss) var dismiss
    func closeThisView(){

        DispatchQueue.main.async {
            self.dismiss()
        }
    }
    
    static var previews: some View {
        Toolbar(closeThisView: closeThisView, toolbarTitle: "comments")
            .preferredColorScheme(.dark)
    }
}

>Solution :

You can use this { }
For example:

struct Toolbar_Previews: PreviewProvider {
    
   static var previews: some View {
        Toolbar(closeThisView: {}, toolbarTitle: "comments")
            .preferredColorScheme(.dark)
    }
}