元素找到了，但是该如何操作，好像不可以点击

ssyybb2005

<a class="W_btn_a btn_34px " tabindex="6" suda-data="key=tblog_weibologin3&value=click_sign" node-type="submitBtn" action-type="btn_submit" href="javascript:void(0)">
<em>登录</em>

也不可以提交submit（）
有什么办法可以打开链接吗
以下是脚本
# encoding:utf-8
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support.ui import Select
from selenium.common.exceptions import NoSuchElementException
from selenium.common.exceptions import NoAlertPresentException
import unittest,time,re

class Mysmalltest(unittest.TestCase):
    def setUp(self):
        self.driver = webdriver.Chrome()
        self.base_url = "http://www.weibo.com"
        self.verificationErrors = []
        self.accept_next_alert = True
   
    def test_mysmall(self):
        driver = self.driver
        driver.get(self.base_url + "/")
        time.sleep(3)
        driver.find_element_by_link_text(u"登录").click()
        time.sleep(2)
        # se=driver.find_element_by_xpath("//*[@id='layer_14805670754181']/div[2]/div[3]/div[3]/div[1]/input")
        # se=driver.find_element_by_xpath("/html/body/div[6]/div[2]/div[3]/div[3]/div[1]/input")
        # se=driver.find_element_by_xpath("//input[@class='W_input' and @name='username']")
        se=driver.find_element_by_xpath("(//input[@name='username'])[3]")
        se.clear()
        # st=driver.find_element_by_xpath("//input[@name='username']")
        # print st
        se.send_keys("1781")
        driver.find_element_by_xpath("(//input[@name='password'])[3]").clear()
        driver.find_element_by_xpath("(//input[@name='password'])[3]").send_keys("00000")
        # driver.find_element_by_xpath("//div[@id='layer_14805667737221']/div[2]/div[3]/div[3]/div[6]/a").click()
        sz=driver.find_element_by_xpath(u"(//a[.='登录'])[3]").click()
        sz.click()   这里报错
        
        time.sleep(3)
sz=driver.find_element_by_xpath(u"(//a[.='登录'])[3]")      这个是定位代码  
求大神帮解惑


错误提示
Traceback (most recent call last):
  File "C:\Users\syb\Desktop\mysmalltest.py", line 34, in test_mysmall
    sz=driver.find_element_by_xpath(u"(//a[.='鐧诲綍'])[3]").click()
  File "D:\Python27\lib\site-packages\selenium-2.45.0-py2.7.egg\selenium\webdriver\remote\webelement.py", line 65, in click
    self._execute(Command.CLICK_ELEMENT)
  File "D:\Python27\lib\site-packages\selenium-2.45.0-py2.7.egg\selenium\webdriver\remote\webelement.py", line 402, in _execute
    return self._parent.execute(command, params)
  File "D:\Python27\lib\site-packages\selenium-2.45.0-py2.7.egg\selenium\webdriver\remote\webdriver.py", line 175, in execute
    self.error_handler.check_response(response)
  File "D:\Python27\lib\site-packages\selenium-2.45.0-py2.7.egg\selenium\webdriver\remote\errorhandler.py", line 166, in check_response
    raise exception_class(message, screen, stacktrace)
ElementNotVisibleException: Message: element not visible
  (Session info: chrome=54.0.2840.59)
  (Driver info: chromedriver=2.25.426923 (0390b88869384d6eb0d5d09729679f934aab9eed),platform=Windows NT 6.1.7601 SP1 x86_64)

若尘_51

为啥有两个click()？去掉第一个.click()
sz=driver.find_element_by_xpath(u"(//a[.='登录'])[3]").click()
sz.click()   这里报错

若尘_51

脚本加上报错的信息附上来看看~~