diff --git a/phototrie/phototrie.py b/phototrie/phototrie.py
index 859b0f8..7699b87 100644
--- a/phototrie/phototrie.py
+++ b/phototrie/phototrie.py
@@ -1,5 +1,6 @@
 import os
 import shutil
+import sys
 from tempfile import mkdtemp
 from tkinter import *
 from typing import List, Tuple, Optional