public function get_contents() {
        global $PAGE;
        if (!empty($this->properties->contents)) {
            if (!isset($this->properties->contentsformat)) {
                $this->properties->contentsformat = FORMAT_HTML;
            }
            $context = context_module::instance($PAGE->cm->id);
            $contents = file_rewrite_pluginfile_urls($this->properties->contents, 'pluginfile.php', $context->id, 'mod_lesson',
                                                     'page_contents', $this->properties->id);  // Must do this BEFORE format_text()!
            return format_text($contents, $this->properties->contentsformat,
                               array('context' => $context, 'noclean' => true,
                                     'overflowdiv' => true));  // Page edit is marked with XSS, we want all content here.
        } else {
            return '';
        }
    }