      def setUp(self):
          class Book(object):
              object_map = {}
  
              def __init__(self, id, title, author):
                  self.id = id
 
</s> remove         Correct bulk update serialization should return the input data.
 </s> add         Incorrect bulk update serialization should return error data. </s> remove                     ret.append(self.from_native(item, None))
                    errors.append(self._errors)
 </s> add                     if update:
                        self._deleted = identity_to_objects.values() </s> remove                 if update:
                    self._deleted = identity_to_objects.values()
                self._errors = any(errors) and errors or []
 </s> add                     self._errors = any(errors) and errors or []
            """
            A data type that can be persisted to a mock storage backend
            with `.save()` and `.delete()`.
            """
      def setUp(self):
          class Book(object):
            """
            A data type that can be persisted to a mock storage backend
            with `.save()` and `.delete()`.
            """
              object_map = {}
  
              def __init__(self, id, title, author):
                  self.id = id
keep add keep keep keep keep
 Add extra tests for errors from incorrect data with multiple create/update 
rest_framework/tests/serializer_bulk_update.py