The problem set involves creating a class called jar, and for it to be used as a cookie jar, it can have cookies added to it through deposit, and then cookies removed through withdraw. The program seems to be working as expected when I run it, but I cannot seem to figure out why I am getting this error:

the problem set involves creating a class called jar and for it to be used as a cookie jar that can have cookies added to it though deposit and then cookies removed through withdraw. the program seems to be working as expected when i run it but i cannot seem to work out why i am getting this error: