The output that I having when running the command sudo apt-get install python-software-properties is:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:The following packages have unmet dependencies:
python-software-properties : Depends: python-gnupginterface but it is not installable
Depends: python-pycurl but it is not installable
E: Unable to correct problems, you have held broken packages.
I went through all some guides for troubleshooting my Ubuntu 16.10 source.list file but nothing did work.
Also, bellow is the output of the command sudo apt-get update
Hit:1 http://us.archive.ubuntu.com/ubuntu precise-updates InRelease
Ign:2 http://security.ubuntu.com/ubuntu yakkety-security InRelease
Ign:3 http://security.ubuntu.com/ubuntu yakkety-security Release .
.
.
.
.
.
.
Ign:97 http://mirrors.digitalocean.com/ubuntu yakkety-backports/multiverse Translation-en_US
Ign:97 http://nyc2.mirrors.digitalocean.com/ubuntu yakkety-backports/multiverse Translation-en_US
Ign:98 http://mirrors.digitalocean.com/ubuntu yakkety-backports/multiverse Translation-en
Ign:98 http://nyc2.mirrors.digitalocean.com/ubuntu yakkety-backports/multiverse Translation-en
Err:39 http://mirrors.digitalocean.com/ubuntu yakkety/multiverse Sources
404 Not Found
Ign:39 http://nyc2.mirrors.digitalocean.com/ubuntu yakkety/multiverse Sources
Err:59 http://mirrors.digitalocean.com/ubuntu yakkety-updates/restricted Sources
404 Not Found
Ign:59 http://nyc2.mirrors.digitalocean.com/ubuntu yakkety-updates/restricted Sources
Err:79 http://mirrors.digitalocean.com/ubuntu yakkety-backports/restricted Sources
404 Not Found
Ign:79 http://nyc2.mirrors.digitalocean.com/ubuntu yakkety-backports/restricted Sources
Reading package lists... Done
W: The repository 'http://security.ubuntu.com/ubuntu yakkety-security 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.
W: http://us.archive.ubuntu.com/ubuntu/dists/precise-updates/InRelease: Signature by key 630239CC130E1A7FD81A27B140976EAF437D05B5 uses weak digest algorithm (SHA1)
W: The repository 'http://mirrors.digitalocean.com/ubuntu yakkety 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.
W: The repository 'http://mirrors.digitalocean.com/ubuntu yakkety-updates 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.
W: The repository 'http://mirrors.digitalocean.com/ubuntu yakkety-backports 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://security.ubuntu.com/ubuntu/dists/yakkety-security/restricted/source/Sources 404 Not Found [IP: 91.189.91.23 80]
E: Failed to fetch http://mirrors.digitalocean.com/ubuntu/dists/yakkety/multiverse/source/Sources 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety/restricted/source/Sources 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety/universe/source/Sources 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety/main/source/Sources 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety/main/binary-amd64/Packages 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety/main/binary-all/Packages 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety/main/i18n/Translation-en_US 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety/main/i18n/Translation-en 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety/restricted/binary-amd64/Packages 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety/restricted/binary-all/Packages 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety/restricted/i18n/Translation-en_US 404 Not Found
E: Failed to fetch http://mirrors.digitalocean.com/ubuntu/dists/yakkety-updates/restricted/source/Sources 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-updates/universe/source/Sources 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-updates/multiverse/source/Sources 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-updates/main/source/Sources 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-updates/main/binary-amd64/Packages 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-updates/main/binary-all/Packages 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-updates/main/i18n/Translation-en 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-updates/main/i18n/Translation-en_US 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-updates/restricted/binary-all/Packages 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-updates/restricted/binary-amd64/Packages 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-updates/restricted/i18n/Translation-en 404 Not Found
E: Failed to fetch http://mirrors.digitalocean.com/ubuntu/dists/yakkety-backports/restricted/source/Sources 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-backports/universe/source/Sources 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-backports/multiverse/source/Sources 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-backports/main/source/Sources 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-backports/main/binary-amd64/Packages 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-backports/main/binary-all/Packages 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-backports/main/i18n/Translation-en 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-backports/main/i18n/Translation-en_US 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-backports/restricted/binary-amd64/Packages 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-backports/restricted/binary-all/Packages 404 Not Found
E: Failed to fetch http://nyc2.mirrors.digitalocean.com/ubuntu/dists/yakkety-backports/restricted/i18n/Translation-en 404 Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.