diff --git a/pkgs/development/python-modules/corner/default.nix b/pkgs/development/python-modules/corner/default.nix
index c69bf902d556..68446453e200 100644
--- a/pkgs/development/python-modules/corner/default.nix
+++ b/pkgs/development/python-modules/corner/default.nix
@@ -47,7 +47,7 @@ buildPythonPackage rec {
 
   dependencies = [ matplotlib ];
 
-  optional-dependencies = {
+  passthru.optional-dependencies = {
     arviz = [ arviz ];
     docs = [
       arviz