The argparse module is an optparse-inspired command line parser that
improves on optparse by:
* handling both optional and positional arguments
* supporting parsers that dispatch to sub-parsers
* producing more informative usage messages
* supporting actions that consume any number of command-line args
* allowing types and actions to be specified with simple callables
instead of hacking class attributes like STORE_ACTIONS or CHECK_METHODS
as well as including a number of other more minor improvements on the
optparse API.
