1 files changed, 2 insertions, 2 deletions

diff --git a/synapse/handlers/acme_issuing_service.py b/synapse/handlers/acme_issuing_service.py

index e1d4224e74..7294649d71 100644
--- a/synapse/handlers/acme_issuing_service.py
+++ b/synapse/handlers/acme_issuing_service.py
@@ -76,9 +76,9 @@ def create_issuing_service(reactor, acme_url, account_key_file, well_known_resou
     )
 
 
-@attr.s
+@attr.s(slots=True)
 @implementer(ICertificateStore)
-class ErsatzStore(object):
+class ErsatzStore:
     """
     A store that only stores in memory.
     """