todo does not output anything when their are no list.

[AnubhaAgrawal]

Actual behavior
When running for the first time or when there are no lists, the todo command outputs nothing. This is very counter-intuitive and may confuse the users.
Expected behavior
When there are no lists, a warning should be displayed saying the same and a suggestion to display help should be shown.
I would like to work on this issue. Can I send a PR?

[untitaker]

This makes sense, and yes, PR is welcome!

I think all that is necessary is a check whether the path is empty, right here.

Also a command to show all task lists would probably be useful for debugging.