diff --git a/src/Engine.ml b/src/Engine.ml
index 624a3df4fbe04c0f2a986368c4eebc80e94e3065..98bd1ed7e5fa7a2de810472c752df014e101b74f 100644
--- a/src/Engine.ml
+++ b/src/Engine.ml
@@ -1498,10 +1498,7 @@ let source : string option =
 (* Reading input data from the source file whose name was given on the command
    line, perform a number of test runs. *)
 
-let none () =
-  ()
-
-let main ?prologue:(prologue=none) fuel =
+let main ?prologue:(prologue=ignore) fuel =
   (* Printing the following two lines at the beginning of every scenario
      allows us to use [Monolith.Support], under the name [Sup], in our
      scenarios. *)