some modularizing and refactoring

nix/nixpkgs/default.nix

@@ -0,0 +1,13 @@
+{
+  nixpkgs = {
+    overlays = [
+      # (_: prev: {
+      #   python312 = prev.python312.override {packageOverrides = _: pysuper: {nose = pysuper.pynose;};};
+      # })
+    ];
+    config = {
+      allowUnfree = true;
+      input-fonts.acceptLicense = true;
+    };
+  };
+}