':param assertion_id:
:param sign:
:return:'

def create_assertion_id_request_response(self, assertion_id, sign=False, **kwargs):

    try:
        (assertion, to_sign) = self.session_db.get_assertion(assertion_id)
    except KeyError:
        raise Unknown
    if to_sign:
        if (assertion.signature is None):
            assertion.signature = pre_signature_part(assertion.id, self.sec.my_cert, 1)
        return signed_instance_factory(assertion, self.sec, to_sign)
    else:
        return assertion
