diff --git a/src/python/jw/pkg/App.py b/src/python/jw/pkg/App.py
index 443b5d1d..894b62aa 100644
--- a/src/python/jw/pkg/App.py
+++ b/src/python/jw/pkg/App.py
@@ -126,10 +126,14 @@ class App(Base):
     def __find_dir(
         self,
         name: str,
-        search_subdirs: list[str] = [],
-        search_absdirs: list[str] = [],
+        search_subdirs: list[str] | None = None,
+        search_absdirs: list[str] | None = None,
         pretty: bool = True,
     ) -> str | None:
+        if search_subdirs is None:
+            search_subdirs = []
+        if search_absdirs is None:
+            search_absdirs = []
 
         def __format_relpath(path: str):
             if path.startswith('./'):
@@ -488,8 +492,8 @@ class App(Base):
     def find_dir(
         self,
         name: str,
-        search_subdirs: list[str] = [],
-        search_absdirs: list[str] = [],
+        search_subdirs: list[str] | None = None,
+        search_absdirs: list[str] | None = None,
         pretty: bool = True,
         throw: bool = False,
     ) -> str | None: