apt update 遇到相关错误： The repository 'xxx' does not have a Release file.

ubuntu@ubuntu:~$ sudo apt update

[sudo] password for ubuntu:

Get:1 file:/var/cuda-repo-9-0-local  InRelease

Ign:1 file:/var/cuda-repo-9-0-local  InRelease

Get:2 file:/var/visionworks-repo  InRelease

Ign:2 file:/var/visionworks-repo  InRelease

Get:3 file:/var/visionworks-sfm-repo  InRelease

Ign:3 file:/var/visionworks-sfm-repo  InRelease

Get:4 file:/var/visionworks-tracking-repo  InRelease

Ign:4 file:/var/visionworks-tracking-repo  InRelease

Get:5 file:/var/cuda-repo-9-0-local  Release [574 B]

Get:6 file:/var/visionworks-repo  Release [1,999 B]

Get:7 file:/var/visionworks-sfm-repo  Release [2,003 B]                                                                          

Get:8 file:/var/visionworks-tracking-repo  Release [2,008 B]                                                                     

Get:5 file:/var/cuda-repo-9-0-local  Release [574 B]                                                                             

Get:6 file:/var/visionworks-repo  Release [1,999 B]                                                                                    

Get:7 file:/var/visionworks-sfm-repo  Release [2,003 B]                                                                                

Get:8 file:/var/visionworks-tracking-repo  Release [2,008 B]                                                                           

Hit:12 http://ports.ubuntu.com/ubuntu-ports xenial InRelease                                                                           

Ign:13 http://ppa.launchpad.net/chris-lea/node.js/ubuntu xenial InRelease                                                              

Hit:15 http://ports.ubuntu.com/ubuntu-ports xenial-updates InRelease                                                                   

Hit:16 http://ports.ubuntu.com/ubuntu-ports xenial-security InRelease                                                                  

Hit:17 http://packages.ros.org/ros/ubuntu xenial InRelease                                                                             

Hit:18 http://realsense-hw-public.s3. ... -repo xenial InRelease                                                    

Ign:19 http://ppa.launchpad.net/jonat ... buntu xenial InRelease                         

Err:20 http://ppa.launchpad.net/chris-lea/node.js/ubuntu xenial Release

  404  Not Found [IP: 91.189.95.83 80]

Err:21 http://ppa.launchpad.net/jonat ... buntu xenial Release

  403  Forbidden [IP: 91.189.95.83 80]

Reading package lists... Done

E: The repository 'http://ppa.launchpad.net/chris-lea/node.js/ubuntu xenial 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 'http://ppa.launchpad.net/jonathonf/python-3.6/ubuntu xenial 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.

$ sudo add-apt-repository -y -r ppa:chris-lea/node.js

$ sudo rm -f /etc/apt/sources.list.d/chris-lea-node_js-*.list