How to create a linked list and call it?

[bowlofred]

It would help to have the entire error message (especially including line numbers).

Your listprint() is a bit off...

     def listprint(self):
        printval = self.val
        while printval is not None:
            print (printval.val)
            printval = printval.next   

I believe self is supposed to be a node. So self.val (which you assign to printval) is an integer.

But then you ask for printval.val. That would be the same thing as self.val.val and isn't right.

I'm not sure why you're checking the val if it's None. Normally I would expect every node to have a particular value, and the .next attribute might be None (but not the val).