diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index ee62b90..2ffd0b8 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -4,7 +4,7 @@ default_language_version:
 repos:
   # Generic 'file quality' testing
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v5.0.0
+    rev: v6.0.0
     hooks:
       # Machine-friendliness
       - id: trailing-whitespace
@@ -25,7 +25,7 @@ repos:
 
   # Python file formatting
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.12.2
+    rev: v0.15.4
     hooks:
       - id: ruff
         args: [--fix, --exit-non-zero-on-fix]
diff --git a/workflow/scripts/powerplants_get_inflow_mwh.py b/workflow/scripts/powerplants_get_inflow_mwh.py
index e417c69..c793f1e 100644
--- a/workflow/scripts/powerplants_get_inflow_mwh.py
+++ b/workflow/scripts/powerplants_get_inflow_mwh.py
@@ -83,8 +83,10 @@ def _estimate_bounded_powerplant_inflow(
         f"Country data for {year} is not unique!"
     )
     annual_powerplant_mwh = plants_by_id.apply(
-        lambda x: annual_national_generation[x.country_id]
-        * national_cap_share_per_powerplant[x.name],
+        lambda x: (
+            annual_national_generation[x.country_id]
+            * national_cap_share_per_powerplant[x.name]
+        ),
         axis="columns",
     )
     hours_in_year = 366 * 24 if isleap(year) else 365 * 24