some code improvements

apps/news/tasks.py

@@ -15,9 +15,8 @@ from notification.models import Subscribe
 @shared_task
 def send_email_with_news(news_ids):
     subscribes = Subscribe.objects.all() \
-        .prefetch_related('subscriber') \
+        .prefetch_related('subscriber', 'subscription_type') \
-        .prefetch_related('subscription_type') \
+        .active()
-        .exclude(unsubscrube_date__isnull=False)
 
     sent_news = models.News.objects.filter(id__in=news_ids)
 
@@ -33,7 +32,7 @@ def send_email_with_news(news_ids):
         country = subscribe.subscription_type.country
 
         if country is None:
-            country_code = subscriber.country_code
+            continue  # subscription_type has no country
 
         else:
             country_code = country.code

apps/notification/models.py

@@ -135,6 +135,13 @@ class Subscriber(ProjectBaseMixin):
         return self.subscription_types.exclude(subscriber__subscribe__unsubscribe_date__isnull=False)
 
 
+class SubscribeQuerySet(models.QuerySet):
+
+    def active(self, switcher=True):
+        """Fetches active subscriptions."""
+        return self.exclude(unsubscribe_date__isnull=not switcher)
+
+
 class Subscribe(ProjectBaseMixin):
     """Subscribe model."""
 
@@ -144,6 +151,8 @@ class Subscribe(ProjectBaseMixin):
     subscriber = models.ForeignKey(Subscriber, on_delete=models.CASCADE)
     subscription_type = models.ForeignKey(SubscriptionType, on_delete=models.CASCADE)
 
+    objects = SubscribeQuerySet.as_manager()
+
     class Meta:
         """Meta class."""