newsupernova/vendor/magento/module-usps/Model/Source/Method.php

<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */

namespace Magento\Usps\Model\Source;

/**
 * Method source
 */
class Method extends Generic
{
    /**
     * Carrier code
     *
     * @var string
     */
    protected $code = 'method';
}