add tzinfo for calculating

billard/models.py

@@ -1,7 +1,7 @@
 import uuid
 from django.db import models
 from django.contrib.auth.models import User
-from datetime import datetime
+from datetime import datetime, timezone
 from . import utils
 from . import tasks
 from django.contrib.auth.models import User
@@ -58,7 +58,7 @@ class Client(models.Model):
         t = Accounting.objects.filter(client_id=self.id, desk_no=desk_no)[:3][::-1]
         a = t[t.__len__() - 1]
         if a.time_to is None:
-            prize = utils.get_prize_for(start=a.time_from, end=datetime.now(), pph=pht)
+            prize = utils.get_prize_for(start=a.time_from, end=datetime.now(timezone.utc), pph=pht)
             if prize != a.prize:
                 a.prize = prize
         return t