public ResultIn this example, the Add method returns a Result type that contains either a successful result (the sum of x and y) or a failure result (an error message indicating that the values must be non-negative). The Result type is determined by a package library such as the Result class in the CSharpFunctionalExtensions package.Add(int x, int y) { if (x < 0 || y < 0) { return Result.Failure ("Values must be non-negative."); } else { return Result.Successful(x + y); } }