Problemas no download automático de arquivos em Python selenium

Question

Eu tenho abaixo o código que funciona bem para navegar por três páginas e clicar em link para baixar o arquivo .csv no firefox. Mas, usando a preferência de perfil, não é possível fazer o download automaticamente. Qualquer ajuda por favor. Eu defini a configuração do perfil no início, está correto ...?

from lib2to3.pgen2 import driver
from selenium import webdriver
import unittest
from webbrowser import browser
from selenium.webdriver.common.keys import Keys
import selenium
import time

class UnitTestExample(unittest.TestCase):

    def setUp(self):
        profile = webdriver.FirefoxProfile()
        profile.set_preference("browser.download.folderList", 2)
        profile.set_preference("browser.download.manager.showWhenStarting", False)
        profile.set_preference("browser.download.dir", "C:\Python34")
        profile.set_preference("browser.helperApps.neverAsk.saveToDisk", "text/csv")

        self.driver = webdriver.Firefox(firefox_profile=profile)  # note that this creates a class instance variable
        self.driver.implicitly_wait(30)  # when testing AJAX this would not be used
        self.base_url = "https://webtac.industrysoftware.automation.siemens.com/webpr/webpr.php?objtype=frames&g_userid=fddd&g_session_id=7311876"  # sets up another class instance variable
        self.verificationErrors = []

    def testWebSite1(self):  # a first test case there can be others
        driver = self.driver  # class instance variable used here
        driver.get(
            "https://webtac.industrysoftware.automation.siemens.com/webpr/webpr.php?objtype=frames&g_userid=a3rgcw&g_session_id=7311876")

        username = driver.find_element_by_id("username")
        password = driver.find_element_by_id("password")

        username.send_keys("username")
        password.send_keys("password")

        ###  driver.find_element_by_class_name("btn btn-primary").send_keys("\n")

        driver.find_element_by_xpath('//button[@type="submit"]').submit()
        time.sleep(30)
        # Call java fuction and web page loads
        driver.execute_script('javascript:parent.gotoSearch(\'advanced\')')
        # Add below dates in input fields
        time.sleep(10)

        driver.switch_to.frame(0)
        time.sleep(10)

        openf = driver.find_element_by_id("openedFrom_dateText")
        opent = driver.find_element_by_id("openedTo_dateText")
        openf.clear();
        openf.send_keys("01-Jan-2015")
        opent.clear();
        opent.send_keys("02-Jan-2015")
        time.sleep(20)
         # Print status
        print(driver.current_url)
        window_before = driver.window_handles[0]
        print(window_before)

        #Button click
        driver.find_element_by_xpath('//input[@type="button"]').click()
        time.sleep(10)

        window_after = driver.window_handles[1]
        driver.switch_to.window(window_after)
        print(driver.current_url)
        driver.find_element_by_link_text("[Comma-Delimited Text (CSV)]").click()
        print(window_after)
        time.sleep(10)
    def tearDown(self):
        self.driver.quit()
        self.assertEqual([], self.verificationErrors)


if __name__ == "__main__":  # allows unittest to start by running this class file
    unittest.main()  # start the main method of unittest