diff --git a/modules/dream2nix/WIP-python-pdm/lib.nix b/modules/dream2nix/WIP-python-pdm/lib.nix
index 737f1135..ea9619a5 100644
--- a/modules/dream2nix/WIP-python-pdm/lib.nix
+++ b/modules/dream2nix/WIP-python-pdm/lib.nix
@@ -196,7 +196,7 @@
   mkExtrasKey = dep @ {extras ? [], ...}:
     if extras == []
     then "default"
-    else lib.concatStringsSep "," extras;
+    else lib.concatStringsSep "," (lib.naturalSort extras);
 
   # Constructs dependency entry for internal use.
   # We could use the pyproject.nix representation directly instead, but it seems