Php 未定义索引：使用laravel导入CSV文件时出现bsd

所以我完全是拉雷维尔的不速之客，我正在尝试一些东西。我想导入一个CSV文件，但当我提交它时会出现此错误

未定义索引：bsd

我的TransactionImport.php文件

<?PHP
 namespace App\Imports;
 use App\Transactions;
 use Maatwebsite\Excel\Concerns\ToModel;
 use Maatwebsite\Excel\Concerns\WithHeadingRow;

 class TransactionsImport implements ToModel,WithHeadingRow
 {
/**
* @param array $row
*
* @return \Illuminate\Database\Eloquent\Model|null
*/
public function model(array $row)
{
    return new Transactions([
        'bsd'     => $row['bsd'],
        'lodgement_reference'    => $row['lodgement_reference'], 
        'account_number'    => $row['account_number'],
        'account_name'    => $row['account_name'],
        'payment_description'    => $row['payment_description'],
        'amount'    => $row['amount'],
        'amount_of_with_holding_tax'    => $row['amount_of_with_holding_tax'],
    ]);
   }
 }

<?PHP

 namespace App\Http\Controllers;

 use Illuminate\Http\Request;
 use App\Imports\TransactionsImport;
 use Maatwebsite\Excel\Facades\Excel;

 class ImportExportController extends Controller
{
 /**
 * @return \Illuminate\Support\Collection
 */
 public function importExportView()
 {
   return view('import');
 }


 /**
 * @return \Illuminate\Support\Collection
 */
  public function import() 
  {
    Excel::import(new TransactionsImport,request()->file('file'));
       
    return back();
  }
  }

<?PHP

namespace App;

use Illuminate\Database\Eloquent\Model;

class Transactions extends Model
{
  protected $fillable = [
    'bsd', 'lodgement_reference', 'account_number', 'account_name', 'payment_description', 'amount', 'amount_of_with_holding_tax'
];
}

---

检查
dd（$row）@sta这给出了一个数据数组：7[▼   “013_664”=>“013-040”“ref_a”=>“ref_B”405268013=>“481626839”“magnum_支持”=>“Guneet Kaur”“test_1”=>“test 2”“001”=>0.02 0=>0]，但数组不包含
bsd
是，但为什么？？？？？？？？