Deleting a non-existent key does not result in an error

[Removed by request]

I'm using Ubuntu 16.04 dev with apt 1.1.3 and if I'm deleting a key with "apt-key del" which does not exist "OK" is being shown and 0 is returned while I would expect an error message to be shown and another value than 0 being returned. Here is an example how it currently looks:

root@ubuntu:~# apt-key del does_not_exist
OK
root@ubuntu:~# echo $?
0

[Removed by request (removed3425744)]

I'm also noticing that trying to delete multiple keys at once does only delete the first key while I would either expect an error message or that all keys get deleted.