Fatal Error

My friend’s website is getting the fatal error :

Fatal error: Call to undefined method Jetpack::is_module_active() in /home3/overbite/public_html/wp-content/themes/comicpress/functions.php on line 71

Lines 70 and on in ../functions.php are as follows:

if (class_exists( 'Jetpack' ) && Jetpack::init()->is_module_active('infinite-scroll')) {
		add_theme_support('infinite-scroll', array(
		 	'type'           => 'scroll',
			'container'      => 'content',
			'posts_per_page' => comicpress_themeinfo('home_post_count')
		) );

He just updated wordpress and comicpress.

website is https://www.overbitecomics.com

How do I fix this? Any help would be appreciated. Thanks.