Ошибка установки Ubuntu

У меня есть установка для ubuntu make, последовали за документом ubuntu make [! ​​d0]

sudo apt-get обновить следующую ошибку: некоторые пакеты W: The repository 'http://ppa.launchpad.net/linuxgndu/adt-raring/ubuntu xenial Release' does not have a Release file. N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use. N: See apt-secure(8) manpage for repository creation and user configuration details. E: Failed to fetch http://ppa.launchpad.net/linuxgndu/adt-raring/ubuntu/dists/xenial/main/binary-amd64/Packages 404 Not Found E: Some index files failed to download. They have been ignored, or old ones used instead.