andrea@Workstation:~$ gpg --edit-key userthree@none.com
gpg (GnuPG) 1.4.20; Copyright (C) 2015 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.


pub  1024R/51476C28  created: 2016-02-19  expires: never       usage: SC
                     trust: unknown       validity: full
sub  1024R/B235DDE0  created: 2016-02-19  expires: never       usage: E
[  full  ] (1). User three <userthree@none.com>

gpg> check
uid  User three <userthree@none.com>
sig!3        51476C28 2016-02-19  [self-signature]
sig!         F868F863 2016-02-19  User one <userone@none.com>