protected function load_course_sections(stdClass $course, navigation_node $coursenode, $sectionnum = null, $cm = null) {
        global $CFG, $SITE;
        require_once($CFG->dirroot.'/course/lib.php');
        if (isset($cm->sectionnum)) {
            $sectionnum = $cm->sectionnum;
        }
        if ($sectionnum !== null) {
            $this->includesectionnum = $sectionnum;
        }
        course_get_format($course)->extend_course_navigation($this, $coursenode, $sectionnum, $cm);
        if (isset($cm->id)) {
            $activity = $coursenode->find($cm->id, self::TYPE_ACTIVITY);
            if (empty($activity)) {
                $activity = $this->load_stealth_activity($coursenode, get_fast_modinfo($course));
            }
        }
   }
protected function load_course_sections(stdClass $course, navigation_node $coursenode, $sectionnum = null, $cm = null) {
        global $CFG, $SITE;
        require_once($CFG->dirroot.'/course/lib.php');
        if (isset($cm->sectionnum)) {
            $sectionnum = $cm->sectionnum;
        }
        if ($sectionnum !== null) {
            $this->includesectionnum = $sectionnum;
        }
        course_get_format($course)->extend_course_navigation($this, $coursenode, $sectionnum, $cm);
        if (isset($cm->id)) {
            $activity = $coursenode->find($cm->id, self::TYPE_ACTIVITY);
            if (empty($activity)) {
                $activity = $this->load_stealth_activity($coursenode, get_fast_modinfo($course));
            }
        }
   }
protected function load_course_sections ( stdClass $ course , navigation_node $ coursenode , $ sectionnum = null , $ cm = null ) { global $ CFG , $ SITE ; require_once ( $ CFG -> dirroot . '/course/lib.php' ) ; if ( isset ( $ cm -> sectionnum ) ) { $ sectionnum = $ cm -> sectionnum ; } if ( $ sectionnum !== null ) { $ this -> includesectionnum = $ sectionnum ; } course_get_format ( $ course ) -> extend_course_navigation ( $ this , $ coursenode , $ sectionnum , $ cm ) ; if ( isset ( $ cm -> id ) ) { $ activity = $ coursenode -> find ( $ cm -> id , self :: TYPE_ACTIVITY ) ; if ( empty ( $ activity ) ) { $ activity = $ this -> load_stealth_activity ( $ coursenode , get_fast_modinfo ( $ course ) ) ; } } }
Loads all of the courses section into the navigation.

This function calls method from current course format, see
{@link format_base::extend_course_navigation()}
If course module ($cm) is specified but course format failed to create the node,
the activity node is created anyway.

By default course formats call the method {@link global_navigation::load_generic_course_sections()}

@param stdClass $course Database record for the course
@param navigation_node $coursenode The course node within the navigation
@param null|int $sectionnum If specified load the contents of section with this relative number
@param null|cm_info $cm If specified make sure that activity node is created (either
in containg section or by calling load_stealth_activity() )
Loads all of the courses section into the navigation .