diff --git a/synapse/server_notices/server_notices_manager.py b/synapse/server_notices/server_notices_manager.py
index 0099bfb81c8a..ed96aa857110 100644
--- a/synapse/server_notices/server_notices_manager.py
+++ b/synapse/server_notices/server_notices_manager.py
@@ -13,8 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
+from typing import Optional
 
 from synapse.api.constants import EventTypes, Membership, RoomCreationPreset
+from synapse.events import EventBase
 from synapse.types import UserID, create_requester
 from synapse.util.caches.descriptors import cached
 
@@ -50,20 +52,21 @@ def is_enabled(self):
         return self._config.server_notices_mxid is not None
 
     async def send_notice(
-        self, user_id, event_content, type=EventTypes.Message, state_key=None
-    ):
+        self,
+        user_id: str,
+        event_content: dict,
+        type: str = EventTypes.Message,
+        state_key: Optional[bool] = None,
+    ) -> EventBase:
         """Send a notice to the given user
 
         Creates the server notices room, if none exists.
 
         Args:
-            user_id (str): mxid of user to send event to.
-            event_content (dict): content of event to send
-            type(EventTypes): type of event
-            is_state_event(bool): Is the event a state event
-
-        Returns:
-            FrozenEvent
+            user_id: mxid of user to send event to.
+            event_content: content of event to send
+            type: type of event
+            is_state_event: Is the event a state event
         """
         room_id = await self.get_or_create_notice_room_for_user(user_id)
         await self.maybe_invite_user_to_room(user_id, room_id)
@@ -89,17 +92,17 @@ async def send_notice(
         return event
 
     @cached()
-    async def get_or_create_notice_room_for_user(self, user_id):
+    async def get_or_create_notice_room_for_user(self, user_id: str) -> str:
         """Get the room for notices for a given user
 
         If we have not yet created a notice room for this user, create it, but don't
         invite the user to it.
 
         Args:
-            user_id (str): complete user id for the user we want a room for
+            user_id: complete user id for the user we want a room for
 
         Returns:
-            str: room id of notice room.
+            room id of notice room.
         """
         if not self.is_enabled():
             raise Exception("Server notices not enabled")
@@ -163,7 +166,7 @@ async def get_or_create_notice_room_for_user(self, user_id):
         logger.info("Created server notices room %s for %s", room_id, user_id)
         return room_id
 
-    async def maybe_invite_user_to_room(self, user_id: str, room_id: str):
+    async def maybe_invite_user_to_room(self, user_id: str, room_id: str) -> None:
         """Invite the given user to the given server room, unless the user has already
         joined or been invited to it.