String escape?

In the samples for Add-Type there is the following code:

    PS C:\>$source = @"
    public class BasicTest
    {
    public static int Add(int a, int b)
    {
    return (a + b);
    }
    public int Multiply(int a, int b)
    {
    return (a * b);
    }
    }
    "@

When I try to enter this from the IDE I just get a bunch of squiggly red lines (errors). What is the correct syntax to get the samples for Add-Type to work?

Thank you.

Kevin Burton