diff --git a/bundles/backup/metadata.py b/bundles/backup/metadata.py
index e04e502..3a8af00 100644
--- a/bundles/backup/metadata.py
+++ b/bundles/backup/metadata.py
@@ -7,7 +7,7 @@ defaults = {
     },
     'backup': {
         'server': None,
-        'paths': {},
+        'paths': set(),
     },
     'systemd-timers': {
         f'backup': {
diff --git a/bundles/postgresql/metadata.py b/bundles/postgresql/metadata.py
index 764c9b8..e0904f2 100644
--- a/bundles/postgresql/metadata.py
+++ b/bundles/postgresql/metadata.py
@@ -20,7 +20,7 @@ defaults = {
         },
         'databases': {},
     },
-    'grafana_rows': {},
+    'grafana_rows': set(),
 }
 
 if node.has_bundle('zfs'):