                          ret.append(self.from_native(item, None))
                          errors.append(self._errors)
  
                      if update:
                          self._deleted = identity_to_objects.values()
  
                      self._errors = any(errors) and errors or []
                  else:
                      self._errors = {'non_field_errors': ['Expected a list of items.']}
              else:
 
</s> remove         self._deleted = None
 </s> add  </s> remove                 ret = []
 </s> add                 ret = RelationsList() </s> remove         removed_relations = []
 </s> add 
                        ret._deleted = identity_to_objects.values()
                          ret.append(self.from_native(item, None))
                          errors.append(self._errors)
  
                      if update:
                        ret._deleted = identity_to_objects.values()
  
                      self._errors = any(errors) and errors or []
                  else:
                      self._errors = {'non_field_errors': ['Expected a list of items.']}
              else:
keep keep keep keep replace keep keep keep keep keep
 Fix model serializer nestesd delete behavior 
rest_framework/serializers.py