diff --git a/sql/swh-init.sql b/sql/swh-init.sql
index b0f6345..c30dc44 100644
--- a/sql/swh-init.sql
+++ b/sql/swh-init.sql
@@ -1,12 +1,13 @@
 create extension if not exists btree_gist;
 create extension if not exists pgcrypto;
 
 create or replace language plpgsql;
 
 create or replace function hash_sha1(text)
-returns text
+    returns text
+    language sql strict immutable
 as $$
-select encode(digest($1, 'sha1'), 'hex')
-$$ language sql strict immutable;
+    select encode(digest($1, 'sha1'), 'hex')
+$$;
 
 comment on function hash_sha1(text) is 'Compute sha1 hash as text';