diff --git a/scripts/add_existing_baseyear.py b/scripts/add_existing_baseyear.py
index 8380edd0..075909d6 100644
--- a/scripts/add_existing_baseyear.py
+++ b/scripts/add_existing_baseyear.py
@@ -257,14 +257,21 @@ def add_power_capacities_installed_before_baseyear(n, grouping_years, costs, bas
 
                     # for offshore the splitting only includes coastal regions
                     inv_ind = [
-                        i for i in inv_ind if (i + name_suffix) in n.generators.index.str
-                        .replace(str(baseyear), str(grouping_year))
+                        i
+                        for i in inv_ind
+                        if (i + name_suffix)
+                        in n.generators.index.str.replace(
+                            str(baseyear), str(grouping_year)
+                        )
                     ]
 
                     p_max_pu = n.generators_t.p_max_pu[
                         [i + name_suffix for i in inv_ind]
                     ]
-                    p_max_pu.columns = [i + name_suffix.replace(str(grouping_year), str(baseyear)) for i in inv_ind]
+                    p_max_pu.columns = [
+                        i + name_suffix.replace(str(grouping_year), str(baseyear))
+                        for i in inv_ind
+                    ]
 
                     n.madd(
                         "Generator",