1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/push/__init__.py b/synapse/push/__init__.py
index 2c23afe8e3..820f6f3f7e 100644
--- a/synapse/push/__init__.py
+++ b/synapse/push/__init__.py
@@ -94,7 +94,7 @@ class Pusher(metaclass=abc.ABCMeta):
         self._start_processing()
 
     @abc.abstractmethod
-    def _start_processing(self):
+    def _start_processing(self) -> None:
         """Start processing push notifications."""
         raise NotImplementedError()