diff --git a/chapter9/with_list_function/ex171c.py b/chapter9/with_list_function/ex171c.py
index 3e6fd4b..48e903f 100644
--- a/chapter9/with_list_function/ex171c.py
+++ b/chapter9/with_list_function/ex171c.py
@@ -12,7 +12,6 @@ graph = {
     "fin": {},
 }
 
-
 costs = {
     "a": 2,
     "b": 2,