fix - compare weight in distribution with parent or none

apps/product/web/api/v1/serializers/quota_distribution_serializers.py

@@ -65,7 +65,10 @@ class QuotaDistributionSerializer(serializers.ModelSerializer):
             if total + amount > quota.quota_weight:
                 raise QuotaWeightException()
         else:
-            if parent_distribution.weight + amount > parent_distribution.weight:
+            children_total = parent_distribution.children.all().aggregate(
+                total=models.Sum('weight')
+            )['total'] or 0
+            if children_total + amount > parent_distribution.weight:
                 raise QuotaWeightException()
 
         if self.instance: