def _add_chrome_proxy_extension(
        chrome_options, proxy_string, proxy_user, proxy_pass):
    """ Implementation of https://stackoverflow.com/a/35293284 for
        https://stackoverflow.com/questions/12848327/
        (Run Selenium on a proxy server that requires authentication.) """
    if not "".join(sys.argv) == "-c":
        # Single-threaded
        proxy_helper.create_proxy_zip(proxy_string, proxy_user, proxy_pass)
    else:
        # Pytest multi-threaded test
        lock = threading.Lock()
        with lock:
            time.sleep(random.uniform(0.02, 0.15))
            if not os.path.exists(PROXY_ZIP_PATH):
                proxy_helper.create_proxy_zip(
                    proxy_string, proxy_user, proxy_pass)
            time.sleep(random.uniform(0.1, 0.2))
    proxy_zip = PROXY_ZIP_PATH
    if not os.path.exists(PROXY_ZIP_PATH):
        # Handle "Permission denied" on the default proxy.zip path
        proxy_zip = PROXY_ZIP_PATH_2
    chrome_options.add_extension(proxy_zip)
    return chrome_options
Implementation of https://stackoverflow.com/a/35293284 for
        https://stackoverflow.com/questions/12848327/
        (Run Selenium on a proxy server that requires authentication.)