#!coding: utf-8

import json


def login():
    pass


def register():
    pass


def writeFile(filename, data):
    pass


def readFile(filename):
    return

def printJson(data):
    print json.dumps(data, indent=4)


def check_user_exists(username):
    if user is 存在:
        return False
    else:
        return True


def authentication(username, password):
    
    return True # return False


def main():
    pass


main()
