diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py
index 802bda2139..cab2fe1a46 100644
--- a/synapse/events/__init__.py
+++ b/synapse/events/__init__.py
@@ -213,7 +213,7 @@ class StrippedStateEvent:
         }
 
     @staticmethod
-    def from_json_dict(raw_stripped_event: JsonDict) -> "StrippedStateEvent" | None:
+    def from_json_dict(raw_stripped_event: JsonDict) -> "StrippedStateEvent | None":
         """
         Given a raw value from an event's `unsigned` field, attempt to parse it into a
         `StrippedStateEvent`.