why add a " ' " before the date formated string?

[videni]

Please use following to reproduce the problem.

I can't use the insertDate method, because I must show datetime based on user timezone. That is why I use the insertText to mimic this behavior. but the insertText method is insane, it will add " ' " before the date formated string, check the picture below.

<?php

use Carbon\Carbon;

require_once 'vendor/autoload.php';

// Example configuration for the xlswriter
$config = [
    'path' => '/var/www/html'
];

// Create a new Excel file
$writer = new \Vtiful\Kernel\Excel($config);
$writer->fileName("example.xlsx")
       ->header(['date1', 'date2', 'date3', 'date4', 'date5']);

// Use the current timestamp
$timestamp = (new DateTime('now', new DateTimezone('GMT+8')))->getTimestamp(); // or use any specific timestamp

$value = Carbon::now('UTC');

$t2 = Carbon::parse($value, 'UTC')
->timezone('GMT+8');

var_dump($t2->toDateTimeString());

// Insert the date with the timestamp
$writer->insertDate(1, 0, $timestamp, 'yyyy-mm-dd hh:mm:ss');

// any string, "hello", no "    '   "  before the output
$writer->insertText(1, 1, "hello", 'yyyy-mm-dd hh:mm:ss');

// there is a "  '   " before the output
$writer->insertText(1, 2, $t2->toDateTimeString(), 'yyyy-mm-dd hh:mm:ss');

// without format ,   there is a "  '   " before the output

$writer->insertText(1, 3, '2024-06-28 09:47:36'); 

// with format ,   there is a "  '   " before the output
$writer->insertText(1, 4, '2024-06-28 09:47:36', 'yyyy-mm-dd hh:mm:ss');

// Output the file
$writer->output();