Command line parsing is a basic need, including amongst other standard
library modules. argparse has many advantages over optparse (not the
least of which is that it has an active maintainer). Several of these
features *can't* be added to optparse whilst maintaining backwards
compatibility, which is what prompted Steven to create argparse in the
first place.

Improvements that I am aware of include:

- handling of standard Windows way of specifying options
- sub-commands
- handling of positional arguments

I had to implement my own technique for handling a sub-command in recent
unittest changes that would have been much simpler if argparse were in
the standard library.