Selenium Python中的窗口切换错误

我有一个要求，我需要执行一些下拉操作，从子窗口的下拉列表中选择一个值，该值在for循环中从父窗口重定向。也就是说，父窗口中有多行&我需要遍历所有行，单击超链接并从下拉列表中选择相同的值。但当我只切换窗口时，我总是面临错误

需要指出的是，子窗口在同一位置打开，即子窗口不是弹出窗口，两个窗口中的元素都位于具有相同名称和id的iFrame下

我已经在事件列表中存储了需要迭代的所有事件值

我有下面的代码片段

import time
from selenium import webdriver
browser = webdriver.Firefox(executable_path=r'M:\Parvej\Softwares\Python-Selenium\geckodriver.exe')
browser.get('<URL ADDRESS>')
emailElem = browser.find_element_by_id('i0116')
emailElem.send_keys('user@gmail.com')
linkElem = browser.find_element_by_id('idSIButton9')
linkElem.click()
time.sleep(10);

list = browser.find_element_by_tag_name('iframe')

iframe1 = browser.find_element_by_id("gsft_main")

browser.switch_to.frame(iframe1)
time.sleep(10)

incident_list = []
for tr_incidents in browser.find_elements_by_partial_link_text('INC'):
    incidents = tr_incidents.text
    incident_list.append(incidents)

print(incident_list)

for inc in incident_list:
    str1=browser.title
    print(str1)
    #get the window handles using window_handles( ) method
    window_before = browser.window_handles[0]
    print(window_before)

    #since the pop-up is now in an iframe
    #DID NOT SWITCH TO IFRAME BCOZ I HAVE ALREADY SWITCHED TO IT ABOVE
    #browser.switch_to.frame(browser.find_element_by_id('gsft_main'))
    inc_elem = browser.find_element_by_link_text(inc)
    inc_elem.click()

    #get the window handle after a new window has opened
    window_after = browser.window_handles[1]

    #switch on to new child window
    browser.switch_to.window(window_after)

    str2=browser.title
    print(str2)
    print(window_after)

    #assert that main window and child window title don't match
    self.assertNotEqual(str1,str2)
    print('This window has a different title')

    #switch back to original window
    browser.switch_to.window(window_before)

    #assert that the title now match
    self.assertEqual(str1,browser.title)

    print('Returned to parent window. Title now match')
    #browser.back()

但是，每次这样做时，我都会出现错误：

window\u after=浏览器。window\u句柄[1] 索引器：列表索引超出范围

请帮我解决这个问题

谢谢和问候