Ошибки на обновлении после попытки установить Python 2.7?

После попытки установить Python 2.7 в моей Ubuntu 17.04:

$ sudo apt-get install software-properties-common
$ sudo add-apt-repository ppa:fkrull/deadsnakes

Я начал получать ошибку каждый раз, когда я выполняю обновление:

$ sudo apt-get update

sudo apt-get update           
Get:1 http://security.ubuntu.com/ubuntu zesty-security InRelease [89.2 kB]
Ign:2 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty InRelease                                                 
Ign:3 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty Release                                                   
Hit:4 http://mirrors.linode.com/ubuntu zesty InRelease                 
Hit:5 http://mirrors.linode.com/ubuntu zesty-updates InRelease
Hit:6 http://mirrors.linode.com/ubuntu zesty-backports InRelease
Ign:7 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main all Packages
Ign:8 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main amd64 Packages
Ign:9 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main i386 Packages
Ign:10 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main Translation-en_US
Ign:11 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main Translation-en
Ign:7 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main all Packages
Ign:8 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main amd64 Packages
Ign:9 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main i386 Packages
Ign:10 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main Translation-en_US
Ign:11 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main Translation-en
Ign:7 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main all Packages
Ign:8 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main amd64 Packages
Ign:9 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main i386 Packages
Ign:10 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main Translation-en_US
Ign:11 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main Translation-en
Ign:7 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main all Packages
Ign:8 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main amd64 Packages
Ign:9 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main i386 Packages
Ign:10 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main Translation-en_US
Ign:11 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main Translation-en
Ign:7 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main all Packages
Ign:8 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main amd64 Packages
Ign:9 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main i386 Packages
Ign:10 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main Translation-en_US
Ign:11 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main Translation-en
Ign:7 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main all Packages
Err:8 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main amd64 Packages
  404  Not Found
Ign:9 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main i386 Packages
Ign:10 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main Translation-en_US
Ign:11 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main Translation-en
Hit:12 https://deb.nodesource.com/node_7.x zesty InRelease
Fetched 89.2 kB in 0s (129 kB/s)
Reading package lists... Done
W: The repository 'http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty 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/fkrull/deadsnakes/ubuntu/dists/zesty/main/binary-amd64/Packages  404  Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.

Какие-либо идеи, почему? Как может зафиксировать это?

Это ошибки, которые я предполагаю:

Err:8 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty/main amd64 Packages
  404  Not Found
W: The repository 'http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu zesty 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/fkrull/deadsnakes/ubuntu/dists/zesty/main/binary-amd64/Packages  404  Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.