diff --git a/pmb/config/sudo.py b/pmb/config/sudo.py
index 1e227534..baa5963e 100644
--- a/pmb/config/sudo.py
+++ b/pmb/config/sudo.py
@@ -3,10 +3,11 @@
 import os
 import shutil
 from functools import lru_cache
+from typing import Optional
 
 
 @lru_cache()
-def which_sudo() -> str | None:
+def which_sudo() -> Optional[str]:
     """Returns a command required to run commands as root, if any.
 
     Find whether sudo or doas is installed for commands that require root.