Speculatively, there are more than 2 Pythons. Python, like perl has become a family of languages. Some time ago Perl Mongers accepted that Perl 6 was not the next version of Perl but a new language in the Perl family. I suspect Python 3 is to Python 2 as Perl 6 is to Perl 5. Google's Go is also a language in the python family I think.