Chrome open then immediately quits after running Selenium test with python

Chrome open then immediately quits after running Selenium test with python. any suggestions? I have searched all over but nothing helps.

from selenium import webdriver
import os

class AutoAlef():
    def test (self):
        driver_location = 'D:\\chromedriver.exe'
        os.environ["webdriver.chrome.driver"] = driver_location
        driver = webdriver.Chrome(driver_location)
        driver.get("http://www.google.com/")

ChromeTest = AutoAlef()
ChromeTest.test()