Giving invalid subcommands to gtt doesn't result in an error

[RonaldFindling]

Manual misstyping or giving wrong arguments in a script doesn't result in an error (neither error exit status nor error message)

Currently:
gtt nonExisting && echo "success status" neither prints an error message nor does the command return a failure code but success instead.

Suggested:
The command returns an non zero exit code and prints an error message e.g. "Unrecognized command gtt nonExisting`

This could be interesting for scripting and it's also interesting for me as a manual user who types commands.