diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index d2d9bef1f..870810e6e 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -530,9 +530,7 @@ class E2eKeysHandler(object):
         # if everything checks out, then store the keys and send notifications
         deviceids = []
         if "master_key" in keys:
-            yield self.store.set_e2e_cross_signing_key(
-                user_id, "master", master_key
-            )
+            yield self.store.set_e2e_cross_signing_key(user_id, "master", master_key)
             deviceids.append(master_verify_key.version)
         if "self_signing_key" in keys:
             yield self.store.set_e2e_cross_signing_key(