Verificar Firma en PDF en SDK PHP

    require __DIR__.'\..\..\vendor\autoload.php';

    use Aspose\PDF\Configuration;
    use Aspose\PDF\Api\PdfApi;

    $config = [
        'LOCAL_FOLDER' => "C:\\Samples\\",
        'PDF_DOCUMENT_NAME' => "sample-signed.pdf",
        'SIGNATURE_NAME' => 'sign1',
    ];

    class PdfSignatures {
        private $pdfApi;
        private $config;

        private function _create_rest_api() {
            $credentials = json_decode(file_get_contents("./Credentials/credentials.json"), true);

            $configAuth = new Configuration();
            $configAuth->setAppKey($credentials['key']);
            $configAuth->setAppSid($credentials['id']);

            $this->pdfApi = new PdfApi(null, $configAuth);
        }

        public function __construct($config) {
            $this->config = $config;
            $this->_create_rest_api();
        }

        public function uploadDocument() {
            $filePath = $this->config['LOCAL_FOLDER'] . $this->config['PDF_DOCUMENT_NAME'];
            $fileData = file_get_contents($filePath);

            $this->pdfApi->uploadFile($this->config['PDF_DOCUMENT_NAME'], $fileData);
            echo "File: '{$this->config['PDF_DOCUMENT_NAME']}' successfully uploaded.\n";
        }

        public function verifySignature(): void {
            if ($this->pdfApi) {
                $response = $this->pdfApi->getVerifySignature($this->config['PDF_DOCUMENT_NAME'], $this->config['SIGNATURE_NAME']);
                if ($response->code === 200) {
                    if ($response->valid == TRUE)
                        echo "getSignatureFields(): verifySignature(): Signature is VALID for the '" . $this->config['PDF_DOCUMENT_NAME'] . "' document.";
                    else
                        echo "getSignatureFields(): verifySignature(): Signature is NOT VALID for the '" . $this->config['PDF_DOCUMENT_NAME'] . "' document.";
                }
            }
        }
    }

    try {
        $signatures = new PdfSignatures($pdfApi, $configParams);
        $signatures->uploadDocument();
        $signatures->getSignatureFields();
    } catch (Exception $e) {
        echo "Error: " . $e->getMessage() . "\n";
    }