A Selenium WebDriver Singleton class

singleton.py

#!/usr/bin/env python
# -*- encoding: utf-8 -*-
# vim: ts=4 sw=4 expandtab ai

from robot.api import logger
from robot.utils import asserts

from selenium import webdriver

class Singleton(object):

    instance = None

    def __new__(cls, base_url, browser='firefox'):

        if cls.instance is None:
            i = object.__new__(cls)
            cls.instance = i
            cls.base_url = base_url
            cls.browser = browser

            if browser == "firefox":
                # Create a new instance of the Firefox driver
                cls.driver = webdriver.Firefox()
            elif browser == "remote":
                # Create a new instance of the Chrome driver
                cls.driver = webdriver.Remote("http://localhost:4444/wd/hub", webdriver.DesiredCapabilities.HTMLUNITWITHJS)
            else:
                # Sorry, we can't help you right now.
                asserts.fail("Support for Firefox or Remote only!")

        else:

            i = cls.instance

        return i

Hi, could you please explain how does this work? I am trying to get selenium chrome driver in multiple modules but failed on almost every solution