I was installing, uninstalling and reinstalling pythons on my mac,
and I think things are screwed up a little.
At first by default, terminal ran Python 3.5 when I typed
# Setting PATH for Python 3.5
# The orginal version is saved in .bash_profile.pysave
Python 2.7.11 (default, Jun 23 2016, 17:25:20)
[GCC 4.2.1 Compatible Apple LLVM 7.3.0 (clang-703.0.31)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
This worked for me: