python3-click-option-group (Option groups missing in Click)

Click is a package for creating powerful and beautiful command line
interfaces (CLI) in Python, but it has no the functionality for
creating option groups.

Option groups are convenient mechanism for logical structuring
CLI, also it allows you to set the specific behavior and set the
relationship among grouped options (mutually exclusive options
for example). Moreover, argparse stdlib package contains this
functionality out of the box.
