diff --git a/pkgs/development/python-modules/railroad-diagrams/default.nix b/pkgs/development/python-modules/railroad-diagrams/default.nix
index b51b7c321869..48237e069767 100644
--- a/pkgs/development/python-modules/railroad-diagrams/default.nix
+++ b/pkgs/development/python-modules/railroad-diagrams/default.nix
@@ -9,6 +9,8 @@ buildPythonPackage (finalAttrs: {
   version = "3.0.1";
   format = "setuptools";
 
+  __structuredAttrs = true;
+
   src = fetchPypi {
     inherit (finalAttrs) pname version;
     hash = "sha256-qRMyuskAyzw2czH6m2mfCJe8+GtyZPZUWGdd9DDQTOM=";