    @jsonapi_attr
    def _check_sum_(self):  # type: ignore [no-redef]
        return None if isinstance(self, flask_sqlalchemy.model.DefaultMeta) \
            else self._check_sum_property if hasattr(self,"_check_sum_property") \
                else None  # property does not exist during initialization

    @_check_sum_.setter
    def _check_sum_(self, value):  # type: ignore [no-redef]
        self._check_sum_property = value

    replace_opt_locking_attr = _check_sum_
