diff --git a/fftcgtool/book.py b/fftcgtool/book.py
index 3695dae..f8f3d64 100644
--- a/fftcgtool/book.py
+++ b/fftcgtool/book.py
@@ -1,6 +1,7 @@
 import dataclasses
 import logging
 import os
+from dataclasses import replace
 
 from PIL import Image