Additional fixes

games/views.py

@@ -85,7 +85,8 @@ def list_sessions(request, filter="", purchase_id="", platform_id="", game_id=""
     # cannot use dataset[0] here because that might be only partial QuerySet
     context["last"] = Session.objects.all().order_by("timestamp_start").last()
     # charts are always oldest->newest
-    context["chart"] = playtime_over_time_chart(dataset.order_by("timestamp_start"))
+    if Session.objects.count() >= 2:
+        context["chart"] = playtime_over_time_chart(dataset.order_by("timestamp_start"))
 
     return render(request, "list_sessions.html", context)