'See :class:`UpdateS3ErrorPage`.'

@sync_performer
def _perform_update_s3_error_page(self, dispatcher, intent):

    new_error_key = intent.error_key
    old_error_key = self.error_key.get(intent.bucket)
    self.error_key[intent.bucket] = new_error_key
    if (old_error_key == new_error_key):
        return None
    return old_error_key
