TwoFer.cs

// ternary operator
public static string Speak(string name="") => $"One for {(name=="" ? "you" : name)}, one for me.";}

// default value for optional argument
public static string Speak(string name="you") => string.Format("One for {0}, one for me.", name);    
    
// null-coalescing assignment operator
public static string Speak(string name = null) => $"One for { name ?? "you"}, one for me.";