diff --git a/distributed/scheduler.py b/distributed/scheduler.py
index b3176eef858..8ce3b218622 100644
--- a/distributed/scheduler.py
+++ b/distributed/scheduler.py
@@ -3922,7 +3922,7 @@ def update_graph(
 
         # TODO: balance workers
 
-    def new_task(self, key, spec, state):
+    def new_task(self, key: str, spec: object, state: str):
         """ Create a new task, and associated states """
         parent: SchedulerState = cast(SchedulerState, self)