Versions of Python:
3 basic versions
Python 1.0 introduced in Jan 1994
Python 2.0 introduced in October 2000
Python 3.0 introduced in Dec 2008

Python-3 not support Python-2
And Python -2 also not support Python -3
Since they are developed for different purposes

There will be no support for Python-2 after year 2020. So, it is recommended to concentrate on Python-3.