public function clearToken($service)
    {
        $service = $this->normalizeServiceName($service);

        $tokens = $this->sessionScope->get(self::SESSION_TOKEN);
        if (array_key_exists($service, $tokens)) {
            unset($tokens, $service);
        }
        $this->sessionScope->set(self::SESSION_TOKEN, $tokens);

        return $this;
    }