diff --git a/apps/counter/api/views.py b/apps/counter/api/views.py
index 1f47d1f..a7330ce 100644
--- a/apps/counter/api/views.py
+++ b/apps/counter/api/views.py
@@ -103,7 +103,7 @@ class LatestStatisticAPIView(APIView, RoleMixin):
                                 for x in DeviceCount.objects.filter(
                 device_id__in=devices).values('device_id').annotate(max_time=Max('data_time'))]
         if total_count_queryset:
-            total_count = sum(map(lambda x: int(x.count), total_count_queryset))
+            total_count = sum(int(device.count) for device in total_count_queryset)
         else:
             total_count = 0
 
@@ -117,7 +117,7 @@ class LatestStatisticAPIView(APIView, RoleMixin):
                 data_time__lt=cur_month, device_id__in=devices).values('device_id').annotate(
                 max_time=Max('data_time'))]
         if one_month_ago_queryset:
-            one_month_ago_count = sum(map(lambda x: int(x.count), one_month_ago_queryset))
+            one_month_ago_count = sum(int(device.count) for device in one_month_ago_queryset)
             cur_month_count = total_count - one_month_ago_count
         else:
             cur_month_count = total_count
@@ -127,7 +127,7 @@ class LatestStatisticAPIView(APIView, RoleMixin):
                                 for x in DeviceCount.objects.filter(
                                     data_time__lt=midnight, device_id__in=devices).values('device_id').annotate(max_time=Max('data_time'))]
         if one_day_ago_queryset:
-            one_day_ago_count = sum(map(lambda x: int(x.count), one_day_ago_queryset))
+            one_day_ago_count = sum(int(device.count) for device in one_day_ago_queryset)
             daily_count = total_count - one_day_ago_count
         else:
             daily_count = 0