diff --git a/flake.nix b/flake.nix
index cbf42ea..c8f56e3 100644
--- a/flake.nix
+++ b/flake.nix
@@ -36,6 +36,7 @@
         "git-from-scratch"
         "graphviz"
         "hamt"
+        "higher-kinded-data"
         "hs-updater"
         "intmap"
         "lambda"
diff --git a/higher-kinded-data/HigherKindedData.ipynb b/higher-kinded-data/HigherKindedData.ipynb
index a856cf4..d27c580 100644
--- a/higher-kinded-data/HigherKindedData.ipynb
+++ b/higher-kinded-data/HigherKindedData.ipynb
@@ -116,7 +116,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 9,
+   "execution_count": null,
    "id": "18484bcc",
    "metadata": {},
    "outputs": [
@@ -147,7 +147,7 @@
    "mimetype": "text/x-haskell",
    "name": "haskell",
    "pygments_lexer": "Haskell",
-   "version": "9.0.2"
+   "version": "9.4.8"
   }
  },
  "nbformat": 4,
diff --git a/higher-kinded-data/default.nix b/higher-kinded-data/default.nix
index 13a00b1..191b9c1 100644
--- a/higher-kinded-data/default.nix
+++ b/higher-kinded-data/default.nix
@@ -1,3 +1,4 @@
+{ system ? builtins.currentSystem }:
 let
   pkgs = import ../pkgs.nix;
   overlay = sel: sup: {
@@ -12,7 +13,7 @@ let
       };
     };
   };
-  nixpkgs = (import pkgs.nixpkgs { overlays = [ overlay ]; });
+  nixpkgs = (import pkgs.nixpkgs { inherit system; overlays = [ overlay ]; });
   jupyterlab = nixpkgs.python3.withPackages (ps: [ ps.jupyterlab ps.notebook ]);
 in nixpkgs.callPackage "${pkgs.ihaskell}/nix/release.nix" { compiler = "ghc948"; }{
   extraEnvironmentBinaries = [ jupyterlab ];