public function render_assign_header(assign_header $header) {
        $o = '';

        if ($header->subpage) {
            $this->page->navbar->add($header->subpage);
            $args = ['contextname' => $header->context->get_context_name(false, true), 'subpage' => $header->subpage];
            $title = get_string('subpagetitle', 'assign', $args);
        } else {
            $title = $header->context->get_context_name(false, true);
        }
        $courseshortname = $header->context->get_course_context()->get_context_name(false, true);
        $title = $courseshortname . ': ' . $title;
        $heading = format_string($header->assign->name, false, array('context' => $header->context));

        $this->page->set_title($title);
        $this->page->set_heading($this->page->course->fullname);

        $o .= $this->output->header();
        $o .= $this->output->heading($heading);
        if ($header->preface) {
            $o .= $header->preface;
        }

        if ($header->showintro) {
            $o .= $this->output->box_start('generalbox boxaligncenter', 'intro');
            $o .= format_module_intro('assign', $header->assign, $header->coursemoduleid);
            $o .= $header->postfix;
            $o .= $this->output->box_end();
        }

        return $o;
    }