'Respond to this request indicating that the association
type or association session type is not supported.'

def answerUnsupported(self, message, preferred_association_type=None, preferred_session_type=None):

    if self.message.isOpenID1():
        raise ProtocolError(self.message)
    response = OpenIDResponse(self)
    response.fields.setArg(OPENID_NS, 'error_code', 'unsupported-type')
    response.fields.setArg(OPENID_NS, 'error', message)
    if preferred_association_type:
        response.fields.setArg(OPENID_NS, 'assoc_type', preferred_association_type)
    if preferred_session_type:
        response.fields.setArg(OPENID_NS, 'session_type', preferred_session_type)
    return response
