diff --git a/wally/suits/io/fio.py b/wally/suits/io/fio.py
index 50bb1fd..2360a55 100644
--- a/wally/suits/io/fio.py
+++ b/wally/suits/io/fio.py
@@ -778,7 +778,7 @@
     def prepare_data(cls, results) -> List[Dict[str, Any]]:
         """create a table with io performance report for console"""
 
-        def key_func(data) -> Tuple(str, str, str, str, int):
+        def key_func(data: FioRunResult) -> Tuple[str, str, str, str, int]:
             tpl = data.summary_tpl()
             return (data.name,
                     tpl.oper,