i'm trying to prevent this alert,

```
Traceback (most recent call last):
  File "app.py", line 171, in <module>
    main()
  File "app.py", line 109, in main
    clipper = driver.find_elements_by_css_selector("div.btn")
  File "/home/blaster/.local/lib/python2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 605, in find_elements_by_css_selector
    return self.find_elements(by=By.CSS_SELECTOR, value=css_selector)
  File "/home/blaster/.local/lib/python2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 983, in find_elements
    'value': value})['value'] or []
  File "/home/blaster/.local/lib/python2.7/site-packages/selenium/webdriver/remote/webdriver.py", line 312, in execute
    self.error_handler.check_response(response)
  File "/home/blaster/.local/lib/python2.7/site-packages/selenium/webdriver/remote/errorhandler.py", line 241, in check_response
    raise exception_class(message, screen, stacktrace, alert_text)
selenium.common.exceptions.UnexpectedAlertPresentException: Alert Text: None
Message: unexpected alert open: {Alert text : }
  (Session info: headless chrome=65.0.3325.181)
  (Driver info: chromedriver=2.35.528139 (47ead77cb35ab2a9a23218b282151362a66cd662),platform=Linux 4.4.0-116-generic x86_64)

```

I have tried to use (from [this answer](https://stackoverflow.com/a/45288632/9137919)) :

```
driver.execute_script("window.alert = function() {};")

```

but it doesn't work, thank you !