public function import_classes( $data ) {
		if ( is_array($data) ) {
			$data = (object) $data;
		}
		$this->classes = array_merge($this->classes, $data->classes);
		$this->classes = array_unique($this->classes);
		$this->classes = apply_filters('nav_menu_css_class', $this->classes, $this, array(), 0);
		$this->class = trim(implode(' ', $this->classes));
	}