private function requestToken()
    {
        $tokenResponse = $this->client->request(
            'GET',
            $this->config->getAuthUrl(),
            $this->config->getAuthHeader()
        );


        $this->token = $tokenResponse->getBody()->getContents();

        $this->tokenExpireTime->modify(
            sprintf('+%s seconds', 3600)
        );
    }