Yoast_Form::get_instance PHP Method

    public static function get_instance()
    {
        if (!self::$instance instanceof self) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    /**
     * Function that outputs the redirect page
     */
    public static function display()
    {
        // Licensing part.
        $license_manager = new Yoast_Plugin_License_Manager(new WPSEO_Product_Premium());
        // Setup constant name.
        $license_manager->set_license_constant_name('WPSEO_LICENSE');
        // Admin header.
        Yoast_Form::get_instance()->admin_header(false);
        if ($license_manager->license_is_valid()) {
            ?>
			<div class="wpseo_content_cell">
				<iframe src="//fast.wistia.net/embed/playlists/5t35e24abt?media_0_0%5BautoPlay%5D=false&amp;media_0_0%5BcontrolsVisibleOnLoad%5D=false&amp;theme=bento&amp;version=v1&amp;videoOptions%5BautoPlay%5D=true&amp;videoOptions%5BvideoHeight%5D=450&amp;videoOptions%5BvideoWidth%5D=800&amp;videoOptions%5BvolumeControl%5D=true" allowtransparency="true" frameborder="0" scrolling="no" class="wistia_playlist" name="wistia_playlist" allowfullscreen mozallowfullscreen webkitallowfullscreen oallowfullscreen msallowfullscreen width="1107" height="450"></iframe>
				<br class="clear">
			</div>
			<br class="clear">
		<?php 
        } else {
            echo '<div class="wpseo-warning">';
            /* translators: %s: 'Yoast SEO Premium' */
            echo '<h2>' . sprintf(__('%s is inactive.', 'wordpress-seo-premium'), 'Yoast SEO Premium') . '</h2>';
            if (current_user_can('manage_options')) {
                /* translators: %s: 'Yoast SEO Premium' */
                echo '<p>' . sprintf(__('Please activate %s to be able to see the videos.', 'wordpress-seo-premium'), 'Yoast SEO Premium') . '</p></div>';
            } else {
                /* translators: %s: 'Yoast SEO Premium' */
                echo '<p>' . sprintf(__('Please ask your site administrator to activate %s to be able to see the videos.', 'wordpress-seo-premium'), 'Yoast SEO Premium') . '</p></div>';
            }
        }
        // Admin footer.
        Yoast_Form::get_instance()->admin_footer(false);
    }