rc@651650656:~$ sudo ppa-purge ppa:ubuntuhandbook1/audacity
Updating packages lists
W: The repository 'http://ppa.launchpad.net/ubuntuhandbook1/audacity/ubuntu xenial Release' does not have a Release file.
W: http://download.ebz.epson.net/dsc/op/stable/debian/dists/lsb3.2/Release.gpg: Signature by key E5220FB7014D0FBDA50DFC2BE5E86C008AA65D56 uses weak digest algorithm (SHA1)
E: Failed to fetch http://ppa.launchpad.net/ubuntuhandbook1/audacity/ubuntu/dists/xenial/main/binary-i386/Packages  404  Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
Warning:  apt-get update failed for some reason
rc@651650656:~$