DbCouponRepository.php

<?php

//...

class DbCouponRepository implements CouponRepositoryInterface
{
    /**
     * @const int
     */
    const PAGE_SIZE = 25;

    /**
     * @var CouponEloquentModel
     */
    private $model;

    /**
     * CouponRepository constructor.
     */
    public function __construct()
    {
        $this->model = new CouponEloquentModel();
    }

    /**
     * Get all coupons.
     *
     * @param null $filterableKeyword
     * @param array $orders
     * @return LengthAwarePaginator
     */
    public function getAllCoupons(
        $filterableKeyword = null,
        array $orders = [
            [
                'column' => 'name',
                'direction' => 'asc'
            ]
        ]
    )
    {
        return (new FetchAllCouponsMethodObject(
            $this->model,
            $filterableKeyword,
            $orders,
            self::PAGE_SIZE)
        )->handle();
    }
}