The argparse module makes writing command line tools in Python easy.
Just briefly describe your command line interface and argparse will
take care of the rest, including:

* parsing the arguments and flags from ``sys.argv``
* converting arg strings into objects for your program
* formatting and printing any help messages
* and much more ...

For those familiar with the optparse module from the Python standard
library, argparse improves on this module in a number of ways,
including:

* handling positional arguments
* supporting sub-commands
* allowing alternative option prefixes like ``+`` and ``/``
* handling zero-or-more and one-or-more style arguments
* producing more informative usage messages
* providing a much simpler interface for custom types and actions