public function lesson_inaccessible($message) {
        global $CFG;
        $output  =  $this->output->box_start('generalbox boxaligncenter');
        $output .=  $this->output->box_start('center');
        $output .=  $message;
        $output .=  $this->output->box('<a href="'.$CFG->wwwroot.'/course/view.php?id='. $this->page->course->id .'">'. get_string('returnto', 'lesson', format_string($this->page->course->fullname, true)) .'</a>', 'lessonbutton standardbutton');
        $output .=  $this->output->box_end();
        $output .=  $this->output->box_end();
        return $output;
    }