How does the tftpd-hpa --verbosity option work?

I'm trying to set up a TFTP server using tftp-hpa, and according to [the manpage](https://linux.die.net/man/8/in.tftpd) I can use the --verbosity option to get more output. Unfortunately I can't find anything that explains what I should pass to this option. How do I use it? * --verbosity loud * --verbosity 5 * --verbosity 255 * --verbosity DEBUG Is this documented anywhere? Nothing I have tried so far produces any messages on stdout.