python selenium模块使用出错解决，Message: 'geckodriver' executable needs to be in PATH

错误代码如下：

File "/usr/local/lib/python2.7/dist-packages/selenium-3.0.0b2-py2.7.egg/selenium/webdriver/firefox/webdriver.py", line 65, in __init__
self.service.start()
File "/usr/local/lib/python2.7/dist-packages/selenium-3.0.0b2-py2.7.egg/selenium/webdriver/common/service.py", line 71, in start
os.path.basename(self.path), self.start_error_message)
selenium.common.exceptions.WebDriverException: Message: 'geckodriver' executable needs to be in PATH. 

Exception AttributeError: "'Service' object has no attribute 'process'" in > ignored

Windows系统解决办法如下：

1、下载geckodriver.exe：
下载地址：https://github.com/mozilla/geckodriver/releases
请根据系统版本选择下载；（如Windows 64位系统）

2、下载解压后将getckodriver.exe复制到Firefox的安装目录下，如（C:\Program Files\Mozilla Firefox），并在环境变量Path中添加路径：C:\Program Files\Mozilla Firefox；

3.重启cmd或IDLE再次运行代码即可

ubuntu16.04环境下 解决方法：
1、下载 geckodriverckod 地址： https://github.com/mozilla/geckodriver/releases
2、解压后将geckodriverckod 存放至 /usr/local/bin/ 路径下即可