Issue #24790: Restore unused function.
diff --git a/Lib/idlelib/StackViewer.py b/Lib/idlelib/StackViewer.py
index 542c0df..4752bfc 100644
--- a/Lib/idlelib/StackViewer.py
+++ b/Lib/idlelib/StackViewer.py
@@ -120,6 +120,9 @@
             sublist.append(item)
         return sublist
 
+    def keys(self):  # unused, left for possible 3rd parcy use
+        return self.object.keys()
+
 def _stack_viewer(parent):  # htest #
     root = tk.Tk()
     root.title("Test StackViewer")