diff --git a/fsl/utils/filetree/filetree.py b/fsl/utils/filetree/filetree.py
index 4bf3f9f1eb485b6757d6485fa1ac00f4275e9d09..5f2c7dfe6164b5cbc16b82f48b3b8f9debad5dea 100644
--- a/fsl/utils/filetree/filetree.py
+++ b/fsl/utils/filetree/filetree.py
@@ -1,5 +1,5 @@
 from pathlib import Path, PurePath
-from typing import Tuple, Optional, Dict, Any, Set
+from typing import Tuple, Optional, List, Dict, Any, Set
 from copy import deepcopy
 from . import parse
 import pickle