Fatal error: Uncaught Error: Class 'Google\AuthHandler\Guzzle6AuthHandler' not found in C:\xampp\htdocs\google-api-php-client\src\AuthHandler\Guzzle7AuthHandler.php:23 Stack trace: #0 {main} thrown in C:\xampp\htdocs\google-api-php-client\src\AuthHandler\Guzzle7AuthHandler.php on line 23