How to change background color in PhpSpreadSheet Excel

<?php
require 'vendor/autoload.php';

use PhpOffice\PhpSpreadsheet\Spreadsheet;
use PhpOffice\PhpSpreadsheet\Writer\Xlsx;

$spreadsheet = new Spreadsheet();
$sheet = $spreadsheet->getActiveSheet();
$sheet->setCellValue('A1', 'Hello World !');
$spreadsheet->getActiveSheet()->getStyle('A1')->getFill()->setFillType(\PhpOffice\PhpSpreadsheet\Style\Fill::FILL_SOLID)->getStartColor()->setARGB('00FF7F');
$writer = new Xlsx($spreadsheet);
$writer->save('hello world.xlsx');
    

<?php
require 'vendor/autoload.php';

use PhpOffice\PhpSpreadsheet\Spreadsheet;
use PhpOffice\PhpSpreadsheet\Writer\Xlsx;

$spreadsheet = new Spreadsheet();
$sheet = $spreadsheet->getActiveSheet();
$sheet->setCellValue('A1', 'Hello World !');
$spreadsheet->getActiveSheet()->getStyle('A1:G1')->getFill()->setFillType(\PhpOffice\PhpSpreadsheet\Style\Fill::FILL_SOLID)->getStartColor()->setARGB('00FF7F');
$writer = new Xlsx($spreadsheet);
$writer->save('hello world.xlsx');