:~$ sudo apt-get update
Hit:1 http://ftp.sjtu.edu.cn/ubuntu bionic InRelease
Hit:2 http://ftp.sjtu.edu.cn/ubuntu bionic-updates InRelease
Hit:3 http://ftp.sjtu.edu.cn/ubuntu bionic-backports InRelease
Hit:4 http://ftp.sjtu.edu.cn/ubuntu bionic-security InRelease
Hit:5 http://packages.microsoft.com/repos/vscode stable InRelease
Hit:6 http://ppa.launchpad.net/deadsnakes/ppa/ubuntu bionic InRelease
Ign:7 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu bionic InRelease
Ign:8 https://launchpad.net/~deadsnakes/+archive/ubuntu/ppa bionic InRelease
Err:9 http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu bionic Release
404 Not Found [IP: 91.189.95.85 80]
Err:10 https://launchpad.net/~deadsnakes/+archive/ubuntu/ppa bionic Release
404 Not Found [IP: 91.189.89.223 443]
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/fkrull/deadsnakes/ubuntu bionic Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'https://launchpad.net/~deadsnakes/+archive/ubuntu/ppa bionic Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
换源吧