MAC 为python3安装 beautifulsoup4

先装pip （终端）输入命令：sudo easy_install pip

安bs4 输入命令：pip install beautifulsoup4

出现错误 
OSError: [Errno 13] Permission denied:

输入命令：sudo easy_install beautifulsoup4

这时把bs装到了Mac系统自带了Python2.7

把beautifulsoup4装到Python3

输入命令：pip3 install beautifulsoup4