حل مشكلة KEYEXPIRED بعد تحديث الــــ MySQL Linux

0
الخطاً :
W: GPG error: http://repo.mysql.com/apt/ubuntu xenial InRelease: The following signatures were invalid: KEYEXPIRED 1550412832  KEYEXPIRED 1550412832  KEYEXPIRED 1550412832
W: The repository 'http://repo.mysql.com/apt/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.
الحل : 
sudo rm -rf /etc/apt/sources.list.d/*
sudo rm -rf /var/lib/apt/lists/*
sudo apt-get update