@classmethod
def _validate_token_class(cls, token_class):
    """Validate token_class.

        Ensures that the token_class supplied has `blacklist_jti` and `get_blacklisted`
        methods

        :param token_class: ORM database model.
        :return: token_class
        :raises RuntimeError if token_class is missing required methods.
        """
    if getattr(token_class, 'blacklist_jti') is None:
        raise RuntimeError(
            'token_class must have a blacklist_jti method that persists data to database'
            )
    if getattr(token_class, 'get_blacklisted') is None:
        raise RuntimeError(
            'token_class must have a get_blacklisted method that returns a list of blacklisted tokens with attr `jti`'
            )
    return token_class
