public static function get( $guid ) {
		$instance = self::get_instance();
		if ( isset( $instance->plugins[ $guid ] ) ) {
			return $instance->plugins[ $guid ];
		} else {
			new \WP_Error( sprintf( __( 'Plugin %s is not registered.', 'sekisyo' ), $guid ), 404, [
				'status' => 404,
			] );
		}
	}