argparse.py

def command(foo, bar, baz=10):
    pass


parser = argparse.ArgumentParser()
parser.add_argument('foo')
parser.add_argument('bar')
parser.add_argument('--baz', default=10)

cli.py

def command(foo, bar, baz):
  pass


def another_command(foo='bar', baz='foo'):
  pass


main = Sly(command, another_command)