1 files changed, 2 insertions, 2 deletions
diff --git a/synapse/storage/databases/main/registration.py b/synapse/storage/databases/main/registration.py
index a06451b7f0..2ed696cc14 100644
--- a/synapse/storage/databases/main/registration.py
+++ b/synapse/storage/databases/main/registration.py
@@ -472,7 +472,7 @@ class RegistrationWorkerStore(SQLBaseStore):
 
     async def get_user_by_external_id(
         self, auth_provider: str, external_id: str
-    ) -> str:
+    ) -> Optional[str]:
         """Look up a user by their external auth id
 
         Args:
@@ -480,7 +480,7 @@ class RegistrationWorkerStore(SQLBaseStore):
             external_id: id on that system
 
         Returns:
-            str|None: the mxid of the user, or None if they are not known
+            the mxid of the user, or None if they are not known
         """
         return await self.db_pool.simple_select_one_onecol(
             table="user_external_ids",