wget http://packages.deepin.com/deepin/pool/main/d/deepin-keyring/deepin-keyring_2019.01.09-1_all.deb

sudo dpkg -i deepin-keyring_2019.01.09-1_all.deb

sudo nano /etc/apt/sources.list.d/deepin.list

deb http://packages.deepin.com/deepin/ lion main contrib non-free
deb-src http://packages.deepin.com/deepin/ lion main contrib non-free

sudo apt update

sudo apt upgrade

sudo apt-get dist-upgrade

sudo apt install dde