Issue with 2 levels of subcommands

[ela34]

I'm trying to implement, 2 level of sub commands: I have attached below a zip file to reproduce the issue based on the following test steps: I do; python mod1.py echo toto And I get: Echoing: toto This is perfect, then I do: python mod1.py test print cool And I get: Printing: cool This is perfect, then I do: python mod1.py --help And I get:

Usage:
    mod1.py [SWITCHES] [SUBCOMMAND [SWITCHES]] args...

Meta-switches
    -h, --help         Prints this help message and quits
    --help-all         Print help messages of all subcommands and quit
    -v, --version      Prints the program's version and quits

Subcommands:
    echo               see 'mod1.py echo --help' for more info
    test               see 'mod1.py test --help' for more info

This is still perfect, but when I do: python mod1.py test --help I get:

Usage:
    mod1.py test [SWITCHES] args...

Meta-switches
    -h, --help         Prints this help message and quits
    --help-all         Print help messages of all subcommands and quit
    -v, --version      Prints the program's version and quits

As you can see, help about subcommands is not displayed at all. Is it a problem with my code? Or is it an issue in Plumbum. Thanks for your help.

mod.zip