diff --git a/exporter.py b/exporter.py
index 9c97c0e77d6d86f0b127cbcdb3d2390ddf49caa1..b8385d656a551a8e365583cc4a65906ebbd3ef3e 100755
--- a/exporter.py
+++ b/exporter.py
@@ -22,7 +22,7 @@ def fetch_metrics(synapse_url, access_token):
     update_room_metrics(rooms)
 
     for room in rooms:
-        statefile = f'state/{room['room_id']}.end'
+        statefile = f"state/{room['room_id']}.end"
         url = f"{synapse_url}/_synapse/admin/v1/rooms/{room['room_id']}/messages"
         messages = []