  
      def books(self):
          return self.Book.object_map.values()
  
      def test_bulk_update_success(self):
          """
 
</s> remove         Correct bulk update serialization should return the input data.
 </s> add         Incorrect bulk update serialization should return error data. </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 []
        """
        Return all the objects in the mock storage backend.
        """
  
      def books(self):
        """
        Return all the objects in the mock storage backend.
        """
          return self.Book.object_map.values()
  
      def test_bulk_update_success(self):
          """
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