Waiting for results -- callbacks

def error(e):
    if isinstance(e, ValueError):
        print "something wrong"
    # what do we do with other errors?
        
def loggedIn(r, protocol):
    protocol.isonline("joe", gotResult, error)

def gotResult(r):
    if r:
        print "joe is online"

def check(protocol):
    f = lambda r: loggedIn(r, protocol)
    protocol.login("itamar", f, error)