diff --git a/evaluation/scripts/plot-throughput-graphs.py b/evaluation/scripts/plot-throughput-graphs.py
index 695eab38..c39a2c0d 100755
--- a/evaluation/scripts/plot-throughput-graphs.py
+++ b/evaluation/scripts/plot-throughput-graphs.py
@@ -170,7 +170,9 @@
 }
 
 
-def load_folders(hostname: str, timestamps: List[str], exclude: List[str]) -> Dict[
+def load_folders(
+    hostname: str, timestamps: List[str], exclude: List[str]
+) -> Dict[
     Bookinfo_Variants,
     Dict[RequestRate, List[Summary]],
 ]:
diff --git a/treefmt.nix b/treefmt.nix
index f07ef595..0a4a3766 100644
--- a/treefmt.nix
+++ b/treefmt.nix
@@ -6,7 +6,8 @@
   programs.statix.enable = true;
   programs.nixfmt-rfc-style.enable = true;
 
-  programs.black.enable = true;
+  programs.ruff.enable = true;
+  programs.ruff.format = true;
   programs.isort.enable = true;
   programs.isort.profile = "black";