Implement 'list-tail' in Scheme

[Katie Burke]

(list-tail '(a b c) 0)

Should return (a b c) according to The Scheme Programming Language but instead, I get this:

scheme>>> (list-tail '(a b c) 0)
Traceback (most recent call last):
File "stdin", line 1, col 2
RunTimeError: unbound variable 'list-tail'