The main function.

def main():
    """ The main function.
    """
    parser = dsargparse.ArgumentParser(main=main)
    subparsers = parser.add_subparsers()

    greeting_cmd = subparsers.add_parser(greeting)
    greeting_cmd.add_argument("title")
    greeting_cmd.add_argument("name")

    goodbye_cmd = subparsers.add_parser(goodbye)
    goodbye_cmd.add_argument("name")

    return parser.parse_and_run()