"A Fake Version Control System"

import plac

commands = 'checkout', 'commit', 'status'

@plac.annotations(url='url of the source code')
def checkout(url):
    "A fake checkout command"
    return ('checkout ', url)

@plac.annotations(message=('commit message', 'option'))
def commit(message):
    "A fake commit command"
    return ('commit ', message)

@plac.annotations(quiet=('summary information', 'flag', 'q'))
def status(quiet):
    "A fake status command"
    return ('status ', quiet)

def __missing__(name):
    return 'Command %r does not exist' % name

def __exit__(etype, exc, tb):
    "Will be called automatically at the end of the call/cmdloop"
    if etype in (None, GeneratorExit): # success
        print('ok')

main = __import__(__name__) # the module imports itself!