diff --git a/solutions/object_oriented_design/deck_of_cards/deck_of_cards.py b/solutions/object_oriented_design/deck_of_cards/deck_of_cards.py
index a4708758..94f8b105 100644
--- a/solutions/object_oriented_design/deck_of_cards/deck_of_cards.py
+++ b/solutions/object_oriented_design/deck_of_cards/deck_of_cards.py
@@ -55,7 +55,7 @@ class BlackJackCard(Card):
         if 1 <= new_value <= 13:
             self._value = new_value
         else:
-            raise ValueError('Invalid card value: {}'.format(new_value))
+            raise ValueError(f'Invalid card value: {new_value}')
 
 
 class Hand(object):