diff --git a/book/external/Useful_python_code b/book/external/Useful_python_code
index 81e9235..c80863d 160000
--- a/book/external/Useful_python_code
+++ b/book/external/Useful_python_code
@@ -1 +1 @@
-Subproject commit 81e923516e06441fb0c04f4946819f5dae9b0a68
+Subproject commit c80863d19f7fde7a452200baa4b4fafe12debc95