Hello everyone, I'm Teddy and just starting to learn Swift 5 with xcode 13. I thought that by creating a Playground I could make short and simple codes to help my understanding of the language. However I get stuck on the same error message : Expressions are not allowed at the top level here is all of my code : // //  Main.swift //  Swift-Playground // import Foundation func greet(_ person: String, nicely: Bool = true) {     if nicely == true {         print("Welcome \(person) !")     } else {         print("Ooh no, it's \(person) again...")     } } greet("teddy") For the moment my playground only contains an assets and Main file. What is missing in code to make simple tests ? Thanks.