如何使用scrapy通过代理获取数据，同时我不使用中间件

Question

我正在使用scrapy来获取数据，我买了一些代理。我读了scrapy doc，我发现如果我想使用代理，我应该写middlewares。现在我的问题是如何在没有middlewares的情况下使用代理？我试过这样：

def start_requests(self):
    name = my_name
    password = password
    proxy = my proxy
    return[
           FormRequest(url,formate={'account':my_name,'password':password},
                      meta={'proxy':proxy},
                      callback=self.after_login)
        ]
def after_login(self, response):
    response.xpath(.....)

我得到TypeError:argument of type 'NoneType' is not iterable 这是Traceback：

Traceback (most recent call last):
  File "/home/think/sjs-project/sjs/venv/local/lib/python2.7/site-packages/twisted/internet/endpoints.py", line 542, in connect
    timeout=self._timeout, bindAddress=self._bindAddress)
  File "/home/think/sjs-project/sjs/venv/local/lib/python2.7/site-packages/twisted/internet/posixbase.py", line 482, in connectTCP
    c = tcp.Connector(host, port, factory, timeout, bindAddress, self)
  File "/home/think/sjs-project/sjs/venv/local/lib/python2.7/site-packages/twisted/internet/tcp.py", line 1165, in __init__
    if abstract.isIPv6Address(host):
  File "/home/think/sjs-project/sjs/venv/local/lib/python2.7/site-packages/twisted/internet/abstract.py", line 522, in isIPv6Address
    if '%' in addr:
TypeError: argument of type 'NoneType' is not iterable

我做错了什么？非常感谢。