cannot upgrade to Ubuntu 20.04

[Nobutaka Kim]

I posted here: https://askubuntu.com/questions/1288704/problems-removing-ppa-using-ppa-purge-for-upgrade-to-ubuntu-20

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.40
ProcVersionSignature: Ubuntu 5.4.0-52.57~18.04.1-generic 5.4.65
Uname: Linux 5.4.0-52-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.9-0ubuntu7.18
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Sun Nov 1 00:01:48 2020
InstallationDate: Installed on 2019-09-16 (411 days ago)
InstallationMedia: Ubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to bionic on 2020-11-01 (0 days ago)

[Chris Guiver (guiverc)]

Change packaged from `ubuntu` to `ubuntu-release-upgrader`

[Brian Murray (brian-murray)]

Reviewing the files from your upgrade attempt you have installed nodejs from a location other than the offical Ubuntu archive. This version of nodejs is greater than the one in the official archive and is keeping some python packages installed which then prevents the upgrade from being calculated. Please remove nodejs along with any other packages from that archive and disable the archive. After that you can try upgrading again and if it still fails open a new bug report. Thanks and good luck!