diff --git a/costs/total_operational_costs.py b/costs/total_operational_costs.py
index dece3fb..ee076f6 100644
--- a/costs/total_operational_costs.py
+++ b/costs/total_operational_costs.py
@@ -34,7 +34,6 @@ class TotalOperationalCosts(CostBase):
       dtype='float'
     )
 
-
   def calculate(self) -> pd.DataFrame:
     """
     Calculate total operational costs