Scrapy的WebDriverWait问题

[mmmaxxx]

from datetime import datetime
from scrapy.spiders import CrawlSpider, Rule
from scrapy.shell import inspect_response
from tencent_app.items import TencentAppItem
import time
import scrapy
from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait

class Yingyongbao(CrawlSpider):
    name = 'yingyongbao_app'
    def __init__(self):
        super(Yingyongbao,self).__init__()
        bid = ['qq']
        self.start_urls = ['http://sj.qq.com/myapp/search.htm?kw=%s' % i for i in bid]
        self.url = 'http://sj.qq.com/myapp/detail.htm?apkName='
        self.driver = webdriver.Firefox()

    def parse(self,response):
        url_set = set()
        self.driver.get(response.url)
        while True:
            try:
                wait = WebDriverWait(self.driver, 2)
                wait.until(lambda driver: driver.find_element_by_xpath('/html/body/div[3]/div[3]/div[2]/a'))
                #time.sleep(1)
                next_page = self.driver.find_element_by_xpath('/html/body/div[3]/div[3]/div[2]/a/i')
                next_page.click()
            except:
                break

我写的翻页程序，模拟浏览器，等待下一页标签出现，不断点击下一页的形式。但我不明白为什么wait = WebDriverWait(self.driver, 12,14)，wait.until(lambda driver: driver.find_element_by_xpath('/html/body/div[3]/div[3]/div[2]/a'))两行代码不管用，会报错

[mmmaxxx]

顶顶顶顶顶顶顶顶顶顶

[mmmaxxx]

顶顶顶顶 的的顶顶顶顶顶

[mmmaxxx]

老天爷爷啊，没人来帮忙嘛。。。

[Maxwelll_]

给我吧把分啊啊啊