(defun primo (lst)
	(car lst))

(defun (setf primo) (val lst)
	(setf (car lst) val))

(defun replace-primo ()
	(let ((x (list 'a 'b 'c)))
		(setf (primo x) 480)
		x))

(deftest test-primo ()
	(check
		(equalp '(480 b c) 
			(replace-primo))))