What does "Expecting member declaration" mean?

I am creating this class as part of a tutorial for Compose navigation.

sealed class Screens(val route: String) {
    object Screen1 : Screens( route: "screen1")
    object Screen2 : Screens( route: "screen2")
}

I am getting the error "Expecting member declaration". What does this error mean in simple terms?

>Solution :

It should either be Screens("screen1") or (if you want to use named arguments) Screens(route="screen1"), with a =.

That error is because the syntax you’re using (with the colon) is confusing the compiler, it doesn’t make sense there