a.py

#!/usr/bin/env python
#-*- coding: utf-8 -*-

# 3 basic data type
a = 'this is a string'
b = ['this is first element in this list', 'this is second element in this list']
c = {'pig':'cute', 'lion':'king'}

b[0] == 'this is first element in this list'

# Boolean
True
False
None

# print
py2: print 'hello world'
py3: print('hello world')

a = 'hello world'

py2: print a
py3: print(a)