Add type hints to synapse.events.*. (#11066)

Except `synapse/events/__init__.py`, which will be done in a follow-up.

1 files changed, 2 insertions, 2 deletions

diff --git a/synapse/events/builder.py b/synapse/events/builder.py

index 50f2a4c1f4..4f409f31e1 100644
--- a/synapse/events/builder.py
+++ b/synapse/events/builder.py
@@ -90,13 +90,13 @@ class EventBuilder:
     )
 
     @property
-    def state_key(self):
+    def state_key(self) -> str:
         if self._state_key is not None:
             return self._state_key
 
         raise AttributeError("state_key")
 
-    def is_state(self):
+    def is_state(self) -> bool:
         return self._state_key is not None
 
     async def build(