diff --git a/scripts/pypsa-de/export_ariadne_variables.py b/scripts/pypsa-de/export_ariadne_variables.py
index 62af1001..6eda64c5 100644
--- a/scripts/pypsa-de/export_ariadne_variables.py
+++ b/scripts/pypsa-de/export_ariadne_variables.py
@@ -248,7 +248,9 @@ def _get_h2_fossil_fraction(n):
         .sum()
     )
 
-    h2_fossil_fraction = total_h2_supply.filter(like="SMR").sum() / total_h2_supply.sum()
+    h2_fossil_fraction = (
+        total_h2_supply.filter(like="SMR").sum() / total_h2_supply.sum()
+    )
 
     return h2_fossil_fraction
 
diff --git a/scripts/pypsa-de/modify_cost_data.py b/scripts/pypsa-de/modify_cost_data.py
index ba588e75..c4746d40 100644
--- a/scripts/pypsa-de/modify_cost_data.py
+++ b/scripts/pypsa-de/modify_cost_data.py
@@ -154,15 +154,23 @@ def carbon_component_fossils(costs, co2_price):
     costs.at[("Fischer-Tropsch", "efficiency"), "value"] = (
         1 / costs.at[("Fischer-Tropsch", "hydrogen-input"), "value"]
     )
-    
+
     # increase FOM of offshore wind connection (fix for costs.csv)
     costs.loc[("offwind-dc-connection-submarine", "FOM"), "value"] = 0.35
-    costs.loc[("offwind-dc-connection-submarine", "FOM"), "unit"] = costs.at[("offwind", "FOM"), "unit"]
+    costs.loc[("offwind-dc-connection-submarine", "FOM"), "unit"] = costs.at[
+        ("offwind", "FOM"), "unit"
+    ]
     costs.loc[("offwind-dc-connection-underground", "FOM"), "value"] = 0.35
-    costs.loc[("offwind-dc-connection-underground", "FOM"), "unit"] = costs.at[("offwind", "FOM"), "unit"]
+    costs.loc[("offwind-dc-connection-underground", "FOM"), "unit"] = costs.at[
+        ("offwind", "FOM"), "unit"
+    ]
     costs.loc[("offwind-ac-connection-submarine", "FOM"), "value"] = 0.35
-    costs.loc[("offwind-ac-connection-submarine", "FOM"), "unit"] = costs.at[("offwind", "FOM"), "unit"]
+    costs.loc[("offwind-ac-connection-submarine", "FOM"), "unit"] = costs.at[
+        ("offwind", "FOM"), "unit"
+    ]
     costs.loc[("offwind-ac-connection-underground", "FOM"), "value"] = 0.35
-    costs.loc[("offwind-ac-connection-underground", "FOM"), "unit"] = costs.at[("offwind", "FOM"), "unit"]
+    costs.loc[("offwind-ac-connection-underground", "FOM"), "unit"] = costs.at[
+        ("offwind", "FOM"), "unit"
+    ]
 
     costs.to_csv(snakemake.output[0])