flake.nix: overlay package into pythonPackages

default.nix

@@ -1,18 +1,25 @@
 { lib
-, python3Packages
+, buildPythonPackage
+
+, setuptools
+, setuptools-scm
+
+, sqlalchemy
 }:
-python3Packages.buildPythonApplication {
+
+buildPythonPackage {
   pname = "libdib";
   version = "unstable";
   src = lib.cleanSource ./.;
 
   format = "pyproject";
 
-  nativeBuildInputs = with python3Packages; [
+  nativeBuildInputs = [
     setuptools
     setuptools-scm
   ];
-  propagatedBuildInputs = with python3Packages; [
+
+  propagatedBuildInputs = [
     sqlalchemy
   ];
 }

flake.nix

@@ -19,15 +19,17 @@
   in {
       packages = forAllSystems (system: pkgs: {
         default = self.packages.${system}.libdib;
-        libdib = pkgs.callPackage ./default.nix {
+        libdib = pkgs.python3Packages.callPackage ./default.nix { };
-          python3Packages = pkgs.python313Packages;
-        };
       });
 
       overlays = {
         default = self.overlays.libdib;
         libdib = final: prev: {
-          inherit (self.packages.${prev.system}) libdib;
+          pythonPackagesExtensions = prev.pythonPackagesExtensions ++ [
+            (python-final: python-prev: {
+              libdib = python-final.callPackage ./default.nix { };
+            })
+          ];
         };
       };