use AlibabaCloud\Client\Exception\ClientException; use AlibabaCloud\Client\Exception\ServerException; use AlibabaCloud\Client\Request\RpcRequest; use AlibabaCloud\Client\Request\RpcRequest; use AlibabaCloud\Client\RequestCheckUtil; $request = new RpcRequest('UserService', 'ListUsers'); // Set the request parameters $request->method('POST') ->product('UserService') ->version('2019-01-01') ->action('ListUsers') ->format('JSON') ->regionId('cn-hangzhou') ->options([ 'query' => [ 'PageSize' => 10, 'PageNumber' => 2, ], ]); // Check the maximum list size RequestCheckUtil::checkMaxListSize($request->options()['query']['PageSize'], 1000, 'PageSize'); // Send the request and handle the response try { $response = $client->rpcRequest($request); // Handle the API response } catch (ClientException $e) { echo $e->getMessage() . PHP_EOL; } catch (ServerException $e) { echo $e->getMessage() . PHP_EOL; }In this example, the checkMaxListSize method is used to validate that the requested page size is not greater than the maximum allowed value of 1000. If the requested page size is greater than 1000, an exception will be thrown with an appropriate error message. The RequestCheckUtil class is part of the Alibaba Cloud SDK for PHP, which is available as a composer package. To use it in your own PHP code, you can include the composer autoload file and instantiate the necessary classes as shown in the example above.