Error in Installation of Plone

When I try to install Plone on my Mac using the unified installer, I get the following error in the logs.

File "/Users/arghyabhattacharya/Plone/tmp/helper_scripts/", line 82
    print _("Copying buildout skeleton")
SyntaxError: invalid syntax

I undersand that this is due to python3 being used.
However, the default version of python that i'm using in 2.7

Testing /Users/arghyabhattacharya/.virtualenvs/plone/bin/python2.7 for Zope/Plone requirements....
/Users/arghyabhattacharya/.virtualenvs/plone/bin/python2.7 looks OK. We will use it.

Rootless install method chosen. Will install for use by system user arghyabhattacharya

Detailed installation log being written to /Users/arghyabhattacharya/Documents/plone/Plone-5.1.4-UnifiedInstaller-r1/install.log
Installing Plone 5.1.4 at /Users/arghyabhattacharya/Plone

Creating Python virtual environment.
Running virtualenv with interpreter /Library/Frameworks/Python.framework/Versions/3.6/bin/python3
Using base prefix '/Library/Frameworks/Python.framework/Versions/3.6'
New python executable in /Users/arghyabhattacharya/Plone/zinstance/bin/python3
Also creating executable in /Users/arghyabhattacharya/Plone/zinstance/bin/python
Installing setuptools, pip, wheel...done.
Installing zc.buildout in virtual environment.
Unpacking buildout cache to /Users/arghyabhattacharya/Plone/buildout-cache

Buildout failed. Unable to continue

Installation has failed.
See the detailed installation log at /Users/arghyabhattacharya/Documents/plone/Plone-5.1.4-UnifiedInstaller-r1/install.log
to determine the cause

The problem is because is using /Library/Frameworks/Python.framework/Versions/3.6/bin/python3 as the interpreter. How can I change this?

I suspect the virtualenv is being lost. Will investigate.

Please try using the "--with-python=/full/path/to/python-2.7" command-line argument and let us know how it goes. Specify the base python 2.7 -- not a virtualenv. The installer creates its own virtualenv, and virtualenvs inside virtualenvs can be problematic.