Error using `getEmailCampaigns`: `Class "\Brevo\Client\Model\AllOfgetEmailCampaignsCampaignsItems" not found`

This API library is truly botched:
```
$brevo_config = \Brevo\Client\Configuration::getDefaultConfiguration()->setApiKey('api-key', $api_key);
$brevo = new \Brevo\Client\Api\EmailCampaignsApi(new \GuzzleHttp\Client(), $brevo_config);
$brevo->getEmailCampaigns(null, 'sent', null, null, null, 100, $offset, null, true);
```