diff --git a/restic_exporter/restic_exporter.py b/restic_exporter/restic_exporter.py
index 04013bf..08cf1db 100644
--- a/restic_exporter/restic_exporter.py
+++ b/restic_exporter/restic_exporter.py
@@ -54,7 +54,7 @@ class ResticExporter:
         self._write_metrics()
 
     def _read_summary_from_systemd(self,):
-        self.summaries = ()
+        self.summaries = []
         journal_obj = journal.Reader()
         journal_obj.seek_realtime(datetime.now() - timedelta(days=1))
         journal_obj.add_match('_EXE=/usr/local/bin/restic')