diff --git a/inventory_provider/tasks/worker.py b/inventory_provider/tasks/worker.py
index 1baad7906511d54c8333b19426485e1a8a8bc1d1..ef7f351e11e2d67f994dd016b4c769a374597365 100644
--- a/inventory_provider/tasks/worker.py
+++ b/inventory_provider/tasks/worker.py
@@ -639,14 +639,15 @@ def _build_service_interface_user_list():
     all_service_ids = set()
     for r in opsdb_interface_map.values():
         all_service_ids |= r['service_ids']
+    all_service_ids = list(all_service_ids)
 
     # dict: service_id[int] -> [list of users]
     service_user_map = dict()
     with db.connection(InventoryTask.config["ops-db"]) as cx:
         # for user in opsdb.get_service_users(cx, list(all_service_ids)):
-        service_users = list(opsdb.get_service_users(cx, list(all_service_ids)))
+        service_users = list(opsdb.get_service_users(cx, all_service_ids))
         for user in service_users:
-                service_user_map.setdefault(
+            service_user_map.setdefault(
                 user['service_id'], []).append(user['user'])
 
     def _users(ifc_key):
@@ -678,7 +679,6 @@ def _build_service_category_interface_list(update_callback=lambda s: None):
             return 'lhcone'
         return None
 
-
     update_callback('loading all known interfaces')
     interfaces = list(_build_service_interface_user_list())
     update_callback(f'loaded {len(interfaces)} interfaces, '