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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def runcmd(self, cmd, args):
        '''Run a single command from pre-parsed arguments.

        This is intended to be run from :meth:`main` or somewhere else
        "at the top level" of the program.  It may raise
        :exc:`exceptions.SystemExit` if an argument such as ``--help``
        that normally causes execution to stop is encountered.

        '''
        dof = getattr(self, 'do_' + cmd, None)
        if dof is None:
            return self.default(' '.join([cmd] + args))
        argf = getattr(self, 'args_' + cmd, None)
        if argf is not None:
            parser = argparse.ArgumentParser(
                prog=cmd,
                description=getattr(dof, '__doc__', None))
            argf(parser)
            argl = parser.parse_args(args)
        else:
            argl = ' '.join(args)
        return dof(argl)