Creates a new refresh token.

    :param identity: The identity of this token, which can be any data that is
                     json serializable. It can also be a python object, in which
                     case you can use the
                     :meth:`~flask_jwt_extended.JWTManager.user_identity_loader`
                     to define a callback function that will be used to pull a
                     json serializable identity out of the object.
    :param expires_delta: A `datetime.timedelta` for how long this token should
                          last before it expires. Set to False to disable
                          expiration. If this is None, it will use the
                          'JWT_REFRESH_TOKEN_EXPIRES` config value
                          (see :ref:`Configuration Options`)
    :param user_claims: Optionnal JSON serializable to override user claims.
    :return: An encoded refresh token

def create_refresh_token(identity, expires_delta=None, user_claims=None):
    """
    Creates a new refresh token.

    :param identity: The identity of this token, which can be any data that is
                     json serializable. It can also be a python object, in which
                     case you can use the
                     :meth:`~flask_jwt_extended.JWTManager.user_identity_loader`
                     to define a callback function that will be used to pull a
                     json serializable identity out of the object.
    :param expires_delta: A `datetime.timedelta` for how long this token should
                          last before it expires. Set to False to disable
                          expiration. If this is None, it will use the
                          'JWT_REFRESH_TOKEN_EXPIRES` config value
                          (see :ref:`Configuration Options`)
    :param user_claims: Optionnal JSON serializable to override user claims.
    :return: An encoded refresh token
    """
    jwt_manager = _get_jwt_manager()
    return jwt_manager._create_refresh_token(identity, expires_delta, user_claims)