1 files changed, 3 insertions, 1 deletions
diff --git a/synapse/storage/push_rule.py b/synapse/storage/push_rule.py
index 30e23445d9..620de71398 100644
--- a/synapse/storage/push_rule.py
+++ b/synapse/storage/push_rule.py
@@ -91,7 +91,9 @@ class PushRuleStore(SQLBaseStore):
         txn.execute(sql, (user_name, relative_to_rule))
         res = txn.fetchall()
         if not res:
-            raise RuleNotFoundException("before/after rule not found: %s" % (relative_to_rule))
+            raise RuleNotFoundException(
+                "before/after rule not found: %s" % (relative_to_rule,)
+            )
         priority_class, base_rule_priority = res[0]
 
         if 'priority_class' in kwargs and kwargs['priority_class'] != priority_class: