diff --git a/flake-parts/formatting.nix b/flake-parts/formatting.nix
index a1b2159..7d2e6b9 100644
--- a/flake-parts/formatting.nix
+++ b/flake-parts/formatting.nix
@@ -1,4 +1,4 @@
-{ self
+{ lib
 , inputs
 , ...
 }: {
@@ -11,5 +11,17 @@
     treefmt.flakeFormatter = true;
     treefmt.programs.nixpkgs-fmt.enable = true;
     treefmt.programs.shellcheck.enable = true;
+    treefmt.settings.formatter.python = {
+      command = "sh";
+      options = [
+        "-eucx"
+        ''
+          ${lib.getExe pkgs.ruff} --fix "$@"
+          ${lib.getExe pkgs.black} "$@"
+        ''
+        "--" # this argument is ignored by bash
+      ];
+      includes = [ "*.py" ];
+    };
   };
 }