Error after Update: warning: use of undefined constant is_user-logged_in-assumed

Hi, I just did a woocommerce plugin update and then this error appeared on the main page:

warning: use of undefined constant is_user-logged_in-assumed ‘is_user_logged_in’ (this will throw and Error in a future version of PHP) in /home/customer/www/URL/public_html/wp-content/themes/woocommerce-theme/header.php on line 77

this is line 77: /my-account”><?php if(is_user_logged_in){ ?>My Account<?php } else { ?>Login <?php } ?>

Please let me know how I can fix this.

Thanks!