python: using mechanize to login shanbay.com

shanbay2.py

from mechanize import Browser
import json

LOGIN_URL = 'http://www.shanbay.com/accounts/login/'
USERNAME = ''
PASSWORD = ''
API = 'http://www.shanbay.com/api/word/'

def login(username=USERNAME, password=PASSWORD, login_url=LOGIN_URL):
    print '[begin login]'
    br = Browser()
    br.open(login_url)
    br.form = br.forms().next()
    br['username'] = username
    br['password'] = password
    print 'logining.....'
    br.submit()
    print 'login success! userinfo: '
    print br.open('http://www.shanbay.com/api/user/info/').get_data()
    print 
    return br

if __name__ == '__main__':
    br = login()
    cmd = ''
    while cmd != 'q':
        cmd = raw_input('Find word: ')
        resp = br.open(API+cmd).get_data()
        res_dict = json.loads(resp)
        print res_dict['voc']['content']
        print res_dict['voc']['definition']
        if res_dict['learning_id'] == 0:
            print 'This word is added to shanbay.'
            br.open('http://www.shanbay.com/api/learning/add/' + cmd)
        print 
        print '--'*20