Be careful where you install software. I recently helped a colleague experiencing python problems:
We attempted to install the internet archive for python to no avail on a mac. So mac already comes with python. I noticed that python was being called from one directory, while downloading to another. So nothing was really working. There was an accidental install of python through home-brew.
So I brew uninstall python and then that fixed the problem. It reverted to calling mac's install of python.
Always watch where you install items. This is the importance of the command line!