Update deck_of_cards.ipynb

solutions/object_oriented_design/deck_of_cards/deck_of_cards.ipynb

@@ -109,7 +109,7 @@
     "        if 1 <= new_value <= 13:\n",
     "            self._value = new_value\n",
     "        else:\n",
-    "            raise ValueError('Invalid card value: {}'.format(new_value))\n",
+    "            raise ValueError(f'Invalid card value: {new_value}')\n",
     "\n",
     "\n",
     "class Hand(object):\n",