Turn Python+selenium use Switch_to_alert to appear strange anomalies

If Switch_to_alert does not work, the most important problem is that more than 1 browsers are turned on, causing alert to crawl. And in the use of Switch_to_alert time will be longer, need to wait a while to complete the work of accept and so on.

The reason is that because multiple browsers are turned on to be unable to locate exactly which browser, such as a browser that has two Firefox at the same time, Webdriver cannot locate the browser to be tested and will not be able to get to the alert window on the test browser.

Turn Python+selenium use Switch_to_alert to appear strange anomalies