  
      def save_object(self, obj, **kwargs):
          obj.save(**kwargs)
  
          if self.allow_add_remove and hasattr(obj, '_removed_relations'):
              [self.delete_object(item) for item in obj._removed_relations]
  
      def delete_object(self, obj):
          obj.delete()
  
      def save(self, **kwargs):
          """
 
</s> remove         if self.allow_add_remove and hasattr(obj, '_removed_relations'):
            [self.delete_object(item) for item in obj._removed_relations]

 </s> add  </s> remove             instance._removed_relations = removed_relations
 </s> add  </s> remove         instance._removed_relations = removed_relations
 </s> add  </s> remove         if self.allow_add_remove and self._deleted:
            [self.delete_object(item) for item in self._deleted]
 </s> add             if self.allow_add_remove and self.object._deleted:
                [self.delete_object(item) for item in self.object._deleted]
        else:
            self.save_object(self.object, **kwargs)         </s> remove         else:
            self.save_object(self.object, **kwargs)
 </s> add 
  
      def save_object(self, obj, **kwargs):
          obj.save(**kwargs)
  



      def delete_object(self, obj):
          obj.delete()
  
      def save(self, **kwargs):
          """
keep keep keep keep replace replace replace keep keep keep keep keep
 Fix model serializer nestesd delete behavior 
rest_framework/serializers.py