diff --git a/src/cdomains/apron/relationDomain.apron.ml b/src/cdomains/apron/relationDomain.apron.ml
index aca2346820..48720b0382 100644
--- a/src/cdomains/apron/relationDomain.apron.ml
+++ b/src/cdomains/apron/relationDomain.apron.ml
@@ -1,6 +1,7 @@
 (** Signatures for relational value domains.
 
     See {!ApronDomain} and {!AffineEqualityDomain}. *)
+
 open GobApron
 open Batteries
 open GoblintCil