fp = webdriver.FirefoxProfile()
fp.set_preference('browser.download.folderList', 2) # custom location
fp.set_preference('browser.download.manager.showWhenStarting', False)
fp.set_preference('browser.download.dir', 'C:Temp')
fp.set_preference('browser.helperApps.neverAsk.saveToDisk', 'application/csv,text/csv,text/comma-separated-values, application/octet-stream')
driver = webdriver.Firefox(profile)
driver.window_handles
driver.swich_to_window(driver.window_handles[0])
url=''
driver.get(url)
pass=driver.find_element_by_id('pswd')
pass.send_keys('xyz123')
driver.find_element_by_id('btnLogin').click()
driver.implicitly_wait(30)
driver.find_element_by_link_text('FileName').click()
driver.switch_to_alert().accept()