diff --git a/companion.py b/companion.py
index 4a827769..d0030748 100644
--- a/companion.py
+++ b/companion.py
@@ -41,7 +41,7 @@ from monitor import monitor
 logger = get_main_logger()
 
 if TYPE_CHECKING:
-    def _(x): return x
+    def _(x: str): return x
 
     UserDict = collections.UserDict[str, Any]  # indicate to our type checkers what this generic class holds normally
 else:
diff --git a/update.py b/update.py
index 5e780a37..024aeb09 100644
--- a/update.py
+++ b/update.py
@@ -21,7 +21,7 @@ from EDMCLogging import get_main_logger
 
 if TYPE_CHECKING:
     import tkinter as tk
-    def _(x): return x
+    def _(x: str): return x
 
 
 logger = get_main_logger()