diff --git a/scripts/add_existing_baseyear.py b/scripts/add_existing_baseyear.py
index 13644897..8eac44f6 100644
--- a/scripts/add_existing_baseyear.py
+++ b/scripts/add_existing_baseyear.py
@@ -285,7 +285,9 @@ def add_power_capacities_installed_before_baseyear(n, grouping_years, costs, bas
                         i for i in inv_ind if (i + name_suffix_by) in n.generators.index
                     ]
 
-                    p_max_pu = n.generators_t.p_max_pu[[i + name_suffix_by for i in inv_ind]]
+                    p_max_pu = n.generators_t.p_max_pu[
+                        [i + name_suffix_by for i in inv_ind]
+                    ]
                     p_max_pu.columns = [i + name_suffix for i in inv_ind]
 
                     n.madd(