public function _pre_wp_nav_menu( $output, $args ) {
		if ( is_customize_preview() ) {
			return $output;
		}

		// For the nav menu widget.
		if ( ! $args->theme_location ) {
			return $output;
		}

		if ( ! $this->_is_caching_nav_menus() ) {
			return $output;
		}

		if ( ! $this->_is_caching_nav_menu( $args->theme_location ) ) {
			return $output;
		}

		$transient = get_transient( $this->_get_transient_id( $args->theme_location ) );
		if ( false !== $transient ) {
			return '<!-- Cached menu ' . $args->theme_location . ' -->' . $transient . '<!-- /Cached menu ' . $args->theme_location . ' -->';
		}

		return $output;
	}