diff --git a/backend/app/utils/threemf_tools.py b/backend/app/utils/threemf_tools.py
index f5921e377..42fb0968c 100644
--- a/backend/app/utils/threemf_tools.py
+++ b/backend/app/utils/threemf_tools.py
@@ -295,19 +295,19 @@ def extract_nozzle_mapping_from_3mf(zf: zipfile.ZipFile) -> dict[int, int] | Non
         physical_extruder_map = data.get("physical_extruder_map")
         if not physical_extruder_map or len(physical_extruder_map) <= 1:
             return None  # Single-nozzle printer
-        
+
         # Check if only one extruder is active.
         # If so, we can skip the mapping and just assign all slots to that extruder.
         # extruder_nozzle_stats format: ["Standard#0|High Flow#0", "Standard#1"]
         # Each entry = one extruder. Format: <NozzleVolumeType>#<count>[|...]
         # #N is the count of physical nozzles of that type (0 = none installed).
         # Types: Standard, High Flow, Hybrid, TPU High Flow
-        
+
         active_extruders = []
-        for stats_str in (data.get("extruder_nozzle_stats") or []):
+        for stats_str in data.get("extruder_nozzle_stats") or []:
             nozzle_counts = [n.partition("#")[2] for n in stats_str.split("|")]
             active_extruders.append(1 if any(c not in ("0", "") for c in nozzle_counts) else 0)
-        
+
         if sum(active_extruders) == 1:
             nozzle_mapping: dict[int, int] = {}
             active_idx = active_extruders.index(1)