# apt install linux-virtual linux-generic snapd
Reading package lists... Done
Building dependency tree       
Reading state information... Done
linux-generic is already the newest version (4.4.0.67.72).
linux-virtual is already the newest version (4.4.0.67.72).
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:
 linux-image-generic : Breaks: snapd (< 2.23.1~) but 2.22.6 is to be installed
 linux-image-virtual : Breaks: snapd (< 2.23.1~) but 2.22.6 is to be installed
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.