diff --git a/synapse/util/frozenutils.py b/synapse/util/frozenutils.py
index 46d3ab4f7d..1fb67df6b9 100644
--- a/synapse/util/frozenutils.py
+++ b/synapse/util/frozenutils.py
@@ -53,4 +53,4 @@ class FrozenEncoder(json.JSONEncoder):
         if isinstance(o, frozendict):
             return dict(o)
 
-        return json.JSONEncoder(self, o)
\ No newline at end of file
+        return json.JSONEncoder(self, o)