docopt : Command-line interface description language. docopt helps you define interface for your command-line app, and automatically generate parser for it.
Clint : Clint is a python module filled with a set of awesome tools for developing commandline applications.
pydantic : Data validation and settings management using python type annotations.
mock : A Python Mocking and Patching Library for Testing
Cliquet : Cliquet is a toolkit to ease the implementation of HTTP microservices, such as data-driven REST APIs.
Command Line Interface Formulation Framework. cliff is a framework for building command line programs. It uses plugins to define sub-commands, output formatters, and other extensions.