add distribution delete exception

apps/product/exceptions.py

@@ -1,5 +1,5 @@
-from rest_framework.exceptions import APIException
 from rest_framework import status
+from rest_framework.exceptions import APIException
 
 
 class QuotaWeightException(APIException):
@@ -18,6 +18,14 @@ class DistributionWeightException(APIException):
     default_code = 'error'
 
 
+class DistributionDeletedException(APIException):
+    """ if distribution is deleted """
+
+    status_code = status.HTTP_400_BAD_REQUEST
+    default_detail = "امکان حذف این توزیع وجود ندارد. ورود به انبار یا توزیعی برای آن ثبت شده است"  # noqa
+    default_code = 'error'
+
+
 class QuotaClosedException(APIException):
     """ if quota is closed, operations can not be done """