Provide a more helpful message if there are too few arguments.

def error(self, message, print_help=False):
        """Provide a more helpful message if there are too few arguments."""
        if 'too few arguments' in message.lower():
            target = sys.argv.pop(0)
            sys.argv.insert(
                0, os.path.basename(target) or os.path.relpath(target))
            message = ("%s. Try getting help with `%s --help`"
                       % (message, " ".join(sys.argv)))
        if print_help:
            self.print_help()
        else:
            self.print_usage()
        sys.stderr.write('\nerror: %s\n' % message)
        sys.exit(2)