metaboxes.php

<?php
use Queulat\Metabox;
use Queulat\Forms\Node_Factory;
use Queulat\Forms\Element\WP_Gallery;
use Queulat\Forms\Element\Input;



class Post_Metabox extends Metabox
{
    public function get_fields() : array
    {
        return [
            Node_Factory::make(
                Input::class,
                [
                    'name' => 'video_url',
                    'label' => 'Video URL',
                    'properties' => [
                        'description' => 'Video url (Vimeo and Youtube support), "Video" post format should be selected'
                    ]
                ]
            ),
            Node_Factory::make(
                WP_Gallery::class,
                [
                    'name' => 'gallery',
                    'label' => 'Image Gallery',
                    'properties' => [
                        'description' => '"Gallery" post format should be selected to show gallery on top'
                    ]
                ]
            )
        ];
    }
    public function sanitize_data(array $data) : array
    {
        $sanitized = [];
        foreach ($data as $key => $val) {
            switch ($key) {
                case 'video_url':
                    $sanitized[$key] = $val;
                    break;
                case 'gallery':
                    $sanitized[$key] = $val;
                    break;
            }
        }
        return $sanitized;
    }
}

new Post_Metabox('post', 'Post format', 'post', ['context' => 'normal']);