(bind-func nth_tailr:[List{!a}*,List{!a}*,i64]*
(lambda (lst idx)
(let ((nt (lambdas (l i cnt)
(if (or (= cnt i) (> cnt i) (null? l))
l
(nt (cdr l)
i
(+ cnt 1))))))
(let ((r (nt lst idx 0)))
r))))