我在Ubuntu Desktop 16.04上使用Selenium
WebDriver，但无法打开浏览器。Firefox更新后出现以下错误（在此之前，所有方法都可以正常工作）：

Traceback (most recent call last):
  File "test.py", line 6, in <module>
    driver = webdriver.Firefox()
  File "/usr/local/lib/python3.5/dist-packages/selenium/webdriver/firefox/webdriver.py", line 81, in __init__
    self.binary, timeout)
  File "/usr/local/lib/python3.5/dist-packages/selenium/webdriver/firefox/extension_connection.py", line 51, in __init__
    self.binary.launch_browser(self.profile, timeout=timeout)
  File "/usr/local/lib/python3.5/dist-packages/selenium/webdriver/firefox/firefox_binary.py", line 68, in launch_browser
    self._wait_until_connectable(timeout=timeout)
  File "/usr/local/lib/python3.5/dist-packages/selenium/webdriver/firefox/firefox_binary.py", line 98, in _wait_until_connectable
    raise WebDriverException("The browser appears to have exited "
selenium.common.exceptions.WebDriverException: Message: The browser appears to have exited before we could connect. If you specified a log_file in the FirefoxBinary constructor, check it for details.