that you didn't know how the plus function works so I'd write a piece of code in my IDE and I'm not should using a shortcut to send that piece of code to the application and the application tells me that 2 plus 3 is 5 yep so it writes the code on the top screen and I get the result on the bottom screen so as as I was saying this allows you to experiment with the library so maybe what happens if I pass three parameters seems to work what happens if I pass a very big number I get an exception what happens if I just pass