mailjet-8.x-2.7/modules/mailjet_subscription/src/Plugin/Derivative/SubscriptionDerivativeBlock.php

<?php

namespace Drupal\mailjet_subscription\Plugin\Derivative;

use Drupal\Component\Plugin\Derivative\DeriverBase;

/**
 * Provides block plugin definitions for Mailjet Signup blocks.
 *
 */
class SubscriptionDerivativeBlock extends DeriverBase
{

  /**
   * {@inheritdoc}
   */
    public function getDerivativeDefinitions($base_plugin_definition)
    {
        $signups = mailjet_subscription_load_multiple();

        foreach ($signups as $signup) {
            $this->derivatives[$signup->id()] = $base_plugin_definition;
            $this->derivatives[$signup->id()]['admin_label'] = t('Mailjet Subscription Form: @name', ['@name' => $signup->name]);
        }

        return $this->derivatives;
    }

}