Python on a Mac

Don't use the default Python installation: it isn't the latest and can result in permissions issues and pacakges being wiped after an OSX update.

1. Install it from Homebrew:
   brew install python
2. Check which version of Python you're using:
   which python
   If it responds '/usr/bin/python' you're using the system one. Read on.
3. Edit the paths to include your Homebrew Python install:
   sudo vi /etc/paths
4. Prepend /usr/local/bin to the list of locations
5. Check the result:
   python
   Should result in the Homebrew version.