selenium3 + python - alert_is_present Location

from selenium import webdriver
from selenium.webdriver.support.wait import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.action_chains import ActionChains
from selenium.webdriver.support.select import Select
import time

driver = webdriver.Chrome()
driver.get("https://www.baidu.com")
mouse = WebDriverWait(driver,10).until(lambda x:x.find_element("link text","设置"))
ActionChains(driver).move_to_element(mouse).perform()
WebDriverWait(driver,10).until(lambda x:x.find_element("link text","搜索设置")).click()
#选择设置项
s = WebDriverWait(driver,10).until(lambda x:x.find_element("id","nr")) 
The Select (S) .select_by_visible_text ( "per page 50")
Point # save button 
JS = "document.getElementsByClassName ( 'prefpanelgo') [0] .click ();" 
driver.execute_script (JS) 
# pop determination result 
Result = EC.alert_is_present () (Driver) 
IF Result: 
    Print ( result.text) 
    result.accept () 
the else: 
    Print ( "Alert does not eject")