accounts/api/modules/internal/helpers/Error.php

<?php
namespace api\modules\internal\helpers;

final class Error {

    public const ACCOUNT_ALREADY_BANNED = 'error.account_already_banned';
    public const ACCOUNT_NOT_BANNED = 'error.account_not_banned';

    public const ACCOUNT_ALREADY_DELETED = 'error.account_already_deleted';
    public const ACCOUNT_NOT_DELETED = 'error.account_not_deleted';

}