1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index 38c4993da0..efb7d26760 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -125,7 +125,7 @@ class RegistrationHandler(BaseHandler):
         localpart: str,
         guest_access_token: Optional[str] = None,
         assigned_user_id: Optional[str] = None,
-    ):
+    ) -> None:
         if types.contains_invalid_mxid_characters(localpart):
             raise SynapseError(
                 400,