private function getAccessToken($authCode, $redirectUri, $tokenUrl)
    {
        return (new Client())->post(
            $tokenUrl,
            [
                'json' => [
                    'grant_type' => 'authorization_code',
                    'code' => $authCode,
                    'client_id' => $this->config()->get('api.oauth2_client_id'),
                    'redirect_uri' => $redirectUri,
                ],
                'auth' => false,
                'verify' => !$this->config()->get('api.skip_ssl'),
            ]
        )->json();
    }