Local Functions in C# 7

LocalFunctions.cs

public class LocalFunctions
{
    public int SomeProduct(int a, int b)
    {
        int Sum(int x, int y)
        {
            return x + y;
        }

        int Difference(int x, int y)
        {
            return x - y;
        }

        int sum = Sum(a, b);
        int difference = Difference(a, b);

        return sum * difference;       
    }
}