diff --git a/astromodels/utils/file_utils.py b/astromodels/utils/file_utils.py
index b70415fe..33cb13de 100644
--- a/astromodels/utils/file_utils.py
+++ b/astromodels/utils/file_utils.py
@@ -3,6 +3,7 @@
 
 import os
 from pathlib import Path
+from typing import Optional
 import numpy as np
 import pkg_resources