and has been in the library for long time the optparse module is newer and more powerful examplethe optparse module csv html py example back in we described the csv html py program in that exercises we proposed extending the program to accept the command-line arguments"maxwidthtaking an integer and "formattaking string the model solution (csv html _ans pyhas -line function to process the arguments here is the start of the main(function for csv html _opt pya version of the program that uses the optparse module to handle the command-line arguments rather than custom functiondef main()parser optparse optionparser(parser add_option("- ""--maxwidth"dest="maxwidth"type="int"help=("the maximum number of characters that can be "output to string fields [default%default]")parser add_option("- ""--format"dest="format"help=("the format used for outputting numbers "[default%default]")parser set_defaults(maxwidth= format= "optsargs parser parse_args(only nine lines of code are neededplus the import optparse statement furthermorewe do not need to explicitly provide - and --help optionsthese are handled by the optparse module to produce suitable usage message using the texts from the help keyword argumentsand with any "%defaulttext replaced with the option' default value notice also that the options now use the conventional unix style of having both short and long option names that start with hyphen short names are convenient for interactive use at the consolelong names are more understandable when used in shell scripts for exampleto set the maximum width to we can use any of - - --maxwidth= or --maxwidth after the command line is parsedthe options are available using the dest namesfor exampleopts maxwidth and opts format any command-line arguments that have not been processed (usually filenamesare in the args list if an error occurs when parsing the command linethe optparse parser will call sys exit( this leads to clean program termination and returns to the operating system as the program' result value conventionallya return value of signifies usage error signifies any other kind of errorand means success when sys exit(is called with no arguments it returns to the operating system