Deepin Desktop is not available for Sparky users any more.
DDE (Deepin Desktop Environment) is a lightweight, elegant desktop environment originally created for the Linux Deepin distribution.
The recommended way to install DDE is installing it via APTus or MinimalGUI/CLI iso image (fresh installation).
DDE can be also installed via APT/Synaptic via 'sparky-desktop-deepin' metapackage (easy way).
sudo apt-get install sparky-desktop-deepin