# apt-get -uVf install usu-archive-keyring
[snip]
Setting up usu-archive-keyring (20160204014526~security1604+1) ...
Warning: apt-key should not be used in scripts (called from postinst maintainerscript of the package usu-archive-keyring)
OK
it works, but there's probably a better way.
it works, but there's probably a better way.