Mario is a very featureful application of similar ideas, and includes multiple built-in transformations, concurrency support, user-defined commands, and extensive documentation.
Thanks for sharing! I hadn't seen Mario before. The async support is super nifty!
From a quick look, it looks like pyp might be a little quicker for some use cases since it doesn't need subcommands, but I'll definitely be updating https://github.com/hauntsaninja/pyp#related-projects
https://github.com/python-mario/mario