diff --git a/apps/counter/api/views.py b/apps/counter/api/views.py
index b9dae14..9840ee4 100644
--- a/apps/counter/api/views.py
+++ b/apps/counter/api/views.py
@@ -197,8 +197,8 @@ class LatestDailyListAPIView(ListAPIView, RoleMixin, DeviceListMixin):
             for item in results:
                 date = item['date']
                 data = device_daily_qs.filter(date=date)
-                total = sum(map(lambda x: x.total, data))
-                increment = sum(map(lambda x: x.increment, data))
+                total = sum(i.total for i in data)
+                increment = sum(i.increment for i in data)
                 item['total'] = total
                 item['increment'] = increment