diff --git a/src/calibre/utils/copy_files.py b/src/calibre/utils/copy_files.py
index d5b00a8a95..262f096678 100644
--- a/src/calibre/utils/copy_files.py
+++ b/src/calibre/utils/copy_files.py
@@ -127,7 +127,7 @@ class WindowsFileCopier:
             winutil.delete_file(make_long_path_useable(src_path))
 
 
-def get_copier() -> Union[UnixFileCopier | WindowsFileCopier]:
+def get_copier() -> Union[UnixFileCopier, WindowsFileCopier]:
     return WindowsFileCopier() if iswindows else UnixFileCopier()