diff --git a/flap/src/fopix/hobixToFopix.ml b/flap/src/fopix/hobixToFopix.ml
index 4a8884a..c6c570f 100644
--- a/flap/src/fopix/hobixToFopix.ml
+++ b/flap/src/fopix/hobixToFopix.ml
@@ -313,6 +313,7 @@ let translate (p : S.t) env =
         add_to_cloture env fname (T.Variable (T.Id "environment")) free_vars
       in
       T.Define (T.Id "environment", new_clot, blocks), env
+    | Some _ -> failwith "Students! This is your job (creation_cloture)!"
   (* Fonction qui initialise une cloture de taille espace
      + la taille de la liste de variable (le nombre de variable libre) *)
   and new_cloture espace list_variable =