diff --git a/program/services.py b/program/services.py
index 8fc245c5607f3c35462fd57609d83d9b17a814e9..6789f61826d8486ef76c6137569cc1a809286b79 100644
--- a/program/services.py
+++ b/program/services.py
@@ -849,7 +849,7 @@ def get_timerange_timeslot_entries(
     if not include_virtual:
         return [make_timeslot_entry(timeslot=timeslot) for timeslot in timeslots]
 
-    if timeslots is None:
+    if not timeslots:
         return []
 
     timeslot_entries = []