python 3 setup slightly incorrect for OSX High Sierra

When using brew install python and adding export PATH=/usr/local/bin:/usr/local/sbin:$PATH to your .profile python still points to the system python executable. Instead you have to add this to the .profile: export PATH="/usr/local/opt/python/libexec/bin:$PATH".

I created a local branch on my computer with this edit but it is saying I don't have permissions to push it. I did a good amount of googling to get this set up so figured I would try to save others the time in the future :)

see first comment on this SA thread: https://stackoverflow.com/questions/5157678/python-homebrew-by-default/48101303#48101303

找到 OS X High Sierra 的 Python 3 和 Homebrew 设置指南，并检查当前如何记录 PATH。更新说明以使用 issue 中描述的 Homebrew Python 路径，然后验证文档中的设置选择的是 Homebrew Python 可执行文件，而不是系统可执行文件。