如何通过此页面上的表单使机械化不失败？

import mechanize

url = 'https://steamcommunity.com'

br=mechanize.Browser(factory=mechanize.RobustFactory())

br.open(url)
print br.request
print br.form
for each in br.forms():
    print each
    print
import mechanize

url = 'https://steamcommunity