environment-variables

When I use VScode to debug my python scripts, the settings cannot be load correctly, but it works fine when I directly run the scripts. How to solve this problem?

When debug

When directly run it prints correctly
![image](https://user-images.githubusercontent.com/26832000/176063

I've noticed that when reading a config file with a field that is not available in env, its custom function won't run.

The reason seems to be that for these kind of fields, parseValue won't be called and therefore the corresponding custom function.

Custom functions runs only if the field was provided as an env argument or with

I want to add support for the -v(--variables) operation that currently exists in the gettext version.
more info here

In the README you can find an example related to spf13/Cobra package. We need similar example but for another cli library :)