cognito code to token 2

public function exchangeAuthorizationCodeForToken($code)
    {
        $client = new CognitoIdentityProviderClient([
            'version' => Yii::$app->params['aws']['version'],
            'region' => Yii::$app->params['aws']['region'],
            'credentials' => [
                'key' => Yii::$app->params['aws']['credentials']['key'],
                'secret' => Yii::$app->params['aws']['credentials']['secret'],
            ]
        ]);

        try {
            $result = $client->exchangeAuthorizationCode([
                'ClientId' => $this->client_id,
                'ClientSecret' => Yii::$app->params['aws']['client_secret'],
                'RedirectUri' => $this->redirect_uri,
                'Code' => $code,
            ]);

            if (isset($result['AccessToken'])) {
                // Access token obtained, use it to retrieve user object
                $accessToken = $result['AccessToken'];

                return $accessToken;


            } else {
                // Error exchanging authorization code for access token
                echo 'Error exchanging authorization code for access token';
            }
        } catch (CognitoIdentityProviderException $e) {
            // Error exchanging authorization code for access token
            echo $e->getMessage();
        }
    }