diff --git a/task.ml b/task.ml
index 8b332ef..214fe2a 100644
--- a/task.ml
+++ b/task.ml
@@ -1,10 +1,5 @@
-let ignore _ = ()
+let [@warning "-27"] ignore x = failwith "Not yet implemented"
 
-let map f u =
-  let rec loop acc = function
-  | [] -> acc
-  | x :: u -> loop (f x :: acc) u in
-  List.rev (loop [] u)
+let [@warning "-27"] map f u = failwith  "Not yet implemented"
 
-let range lo =
-  let rec loop u i = if i < lo then u else loop (i :: u) (i - 1) in loop []
\ No newline at end of file
+let [@warning "-27"] range lo hi = failwith "Not yet implemented"