code: def get_signin_vcode(cookie, codeString):
      '''获取登录时的验证码图片.
  
      codeString - 调用check_login()时返回的codeString.
      '''
      url = ''.join([
          const.PASSPORT_BASE,
          'cgi-bin/genimage?',
          codeString,
      ])
      headers={
          'Cookie': cookie.header_output(),
          'Referer': const.REFERER,
      }
      req = net.urlopen(url, headers=headers)
      if req:
          return req.data
      else:
          return Nonf get_signin_vcode(cookie, codeString):
      '''获取登录时的验证码图片.
  
      codeString - 调用check_login()时返回的codeString.
      '''
      url = ''.join([
          const.PASSPORT_BASE,
          'cgi-bin/genimage?',
          codeString,
      ])
      headers={
          'Cookie': cookie.header_output(),
          'Referer': const.REFERER,
      }
      req = net.urlopen(url, headers=headers)
      if req:
          return req.data
      else:
          return None
docs: 获取登录时的验证码图片.
  
      codeString - 调用check_login()时返回的codeString.