The program usage message that will printed out if
parse_args finds a help option, %prog is substituted with the
value of the prog argument.
options
A list of of OptionParserOption instances that will
define how parse_args reacts to command line options.
OptionParserOption instances are usually created by make_option
and can also be added to an existing OptionParser instance via the
add_option function.
description
Additional text for print_help to print out between
usage statement and options statement
epilogue
Additional text for print_help to print out after
the options statement
providing 
.