akaunting/app/Imports/Purchases/Sheets/BillTransactions.php

<?php

namespace App\Imports\Purchases\Sheets;

use App\Abstracts\Import;
use App\Models\Banking\Transaction as Model;
use App\Http\Requests\Banking\Transaction as Request;

class BillTransactions extends Import
{
    public function model(array $row)
    {
        return new Model($row);
    }

    public function map($row): array
    {
        $row = parent::map($row);

        $row['type'] = 'expense';

        return $row;
    }

    public function rules(): array
    {
        return (new Request())->rules();
    }
}