ArgumentParser. add_subparsers ( [ title ] [ , description ] [ , prog ] [ , parser_class ] [ , action ] [ , option_string ] [ , dest ] [ , help ] [ , metavar ] ) Many programs split up their functionality into a number of sub-commands, for example, the svn program can invoke sub-commands like svn checkout , svn update , and svn commit . Splitting up functionality this way can be a particularly good idea when a program performs several different functions which require different kinds of command-line arguments. ArgumentParser supports the creation of such sub-commands with the add_subparsers() method. The add_subparsers() method is normally called with no arguments and returns a special action object. This object has a single method, add_parser() , which takes a command name and any ArgumentParser constructor arguments, and ret...