set media lock based on membership

   add_filter('wplms_course_finished', 'check_if_the_user_is_free', 10, 5);
        add_filter('wplms_unit_mark_complete', 'check_if_the_user_is_free', 10, 5);

        function check_if_the_user_is_free($flag, $user_id) {
            //$unit_lock = vibe_get_option('nextunit_access');
            //$uno = "ciao1";
            //$due = "ciao2";
            //$stampavera = '<a href="#" id="next_unit" data-unit="' . $units[$next] . '" class="' . $class . '">' . __('Next Unit', 'vibe') . '</a>';
            $membership_ids = 4; //4 is the id of free membership level
            $user_id2 = get_current_user_id();

            if (!pmpro_hasmembershiplevel($membership_ids, $user_id2)) {
                //return 1; // Continue with process
                return 1;
            } else {
              
               // HOW I INSERT HERE TO UNSET THE LOCK UNIT AND SEE NEXT UNIT AND PREVOIUS UNIT ?????
            }
            return $flag;
        }