Не могу sudo apt-get update

Я попытался переустановить pip, но, похоже, проблема в расположении некоторых файлов, связанных с менеджером обновлений.

sudo apt-get install python-pip
[sudo] password for benoit: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: The package update-manager needs to be reinstalled, but I can't find an archive for it.

И затем я получаю следующее от попытки обновить менеджер обновлений пакетов.

$ sudo apt-get update
    Hit:1 http://archive.canonical.com/ubuntu xenial InRelease
    Get:2 http://ppa.launchpad.net/otto-kesselgulasch/gimp/ubuntu xenial InRelease [17,5 kB]            
    Hit:3 http://ca.archive.ubuntu.com/ubuntu xenial InRelease                                          
    Hit:4 http://ca.archive.ubuntu.com/ubuntu xenial-security InRelease                                 
    Hit:5 http://ppa.launchpad.net/teejee2008/ppa/ubuntu xenial InRelease                               
    Ign:6 http://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.4 InRelease                           
    Hit:7 http://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.4 Release  
    Ign:8 http://dl.google.com/linux/chrome/deb stable InRelease            
    Ign:9 http://dl.google.com/linux/earth/deb stable InRelease
    Ign:10 http://dl.google.com/linux/talkplugin/deb stable InRelease
    Ign:2 http://ppa.launchpad.net/otto-kesselgulasch/gimp/ubuntu xenial InRelease
    Hit:11 http://dl.google.com/linux/chrome/deb stable Release
    Hit:12 http://dl.google.com/linux/earth/deb stable Release
    Hit:15 http://dl.google.com/linux/talkplugin/deb stable Release
    Fetched 17,5 kB in 0s (29,9 kB/s)                 
    Reading package lists... Done
    W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:24 and /etc/apt/sources.list.d/google-chrome.list:3
    W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:24 and /etc/apt/sources.list.d/google-chrome.list:3
    W: Target Translations (main/i18n/Translation-en_US) is configured multiple times in /etc/apt/sources.list:24 and /etc/apt/sources.list.d/google-chrome.list:3
    W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:24 and /etc/apt/sources.list.d/google-chrome.list:3
    W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list:24 and /etc/apt/sources.list.d/google-chrome.list:3
    W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list:24 and /etc/apt/sources.list.d/google-chrome.list:3
    W: GPG error: http://ppa.launchpad.net/otto-kesselgulasch/gimp/ubuntu xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 3BDAAC08614C4B38
    W: The repository 'http://ppa.launchpad.net/otto-kesselgulasch/gimp/ubuntu xenial InRelease' is not signed.
    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: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:24 and /etc/apt/sources.list.d/google-chrome.list:3
    W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:24 and /etc/apt/sources.list.d/google-chrome.list:3
    W: Target Translations (main/i18n/Translation-en_US) is configured multiple times in /etc/apt/sources.list:24 and /etc/apt/sources.list.d/google-chrome.list:3
    W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:24 and /etc/apt/sources.list.d/google-chrome.list:3
    W: Target DEP-11 (main/dep11/Components-amd64.yml) is configured multiple times in /etc/apt/sources.list:24 and /etc/apt/sources.list.d/google-chrome.list:3
    W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list:24 and /etc/apt/sources.list.d/google-chrome.list:3

Затем я попытался восстановить файл source.list, который, похоже, не решил проблему. Вот мой файл source.list, как сейчас.

source.list

Я не совсем понимаю, где я должен расследовать дальше. Может ли кто-нибудь помочь?