Mac defaulting Python 2.7 when programming

Hi,

At the moment, I'm learning Python online and at school and I want to do some coding using python on my mac (I use a different laptop for school). But python seems to be defaulting to python 2.7.

I know this by doing the following:

import sys

print sys.version

I've tried it on different text editors (Sublime and Geany) but it won't change. I've reinstalled python 3.4 and 3.5 but no change.

Is anyone also experiencing this problem and does someone have a (relatively easy and safe) method to get me using 3,5?

Thanks!