Unexpected log_level behaviour

[pataquets]

As I'm trying mongodb-proxy, I've found that using different --log_level command line values, exclude other log level messages.
For example, running the proxy with --log_level info and connecting prints INFO messages as expected. However, if I do the same with --log_level debug, DEBUG level messages print, but not the INFO level ones, as I expect. I expect DEBUG level to also include lower log levels, as most softwares do.
I'm logging to stdio.

Other things I tried:

• Passing two --log_level command switches, one for each value.
• Passing the value info,debug to the --log_level command switch.

Is this the intended behaviour? Am I doing it wrong?
Most of time, ERROR or INFO levels are OK, but raising to DEBUG when troubleshooting should not prevent other messages to print.
TIA.

[pataquets]

@christkv : ping?