update subscriber serializer

apps/notification/serializers/common.py

@@ -9,14 +9,13 @@ class SubscribeSerializer(serializers.ModelSerializer):
     """Subscribe serializer."""
 
     email = serializers.EmailField(required=False, source='send_to')
-    state_display = serializers.CharField(source='get_state_display', read_only=True)
 
     class Meta:
         """Meta class."""
 
         model = models.Subscriber
-        fields = ('email', 'state', 'state_display')
-        read_only_fields = ('state', 'state_display')
+        fields = ('email', 'state',)
+        read_only_fields = ('state',)
 
     def validate(self, attrs):
         """Validate attrs."""