selenium 实现多窗口切换

from selenium import webdriver
driver = webdriver.Chrome()
driver.get('http://www.baidu.com')
driver.maximize_window()
current_window = driver.current_window_handle  #获取当前页面的句柄
print(current_window)
driver.find_element_by_link_text('新闻').click()
all_handle = driver.window_handles
for handle in all_handle:
    if handle != current_window:
        print(handle)
        driver.switch_to_window(handle)  #切换窗口句柄
        driver.get_screenshot_as_file('pic.png')
        driver.close()
driver.switch_to_window(current_window)  # 切换到之前的窗口