Py2 -> Py3 is not that hard (when you don't step into troubles with system functions and Unicode) but porting libraries can be very hard, because some of them a

Py2 -> Py3 is not that hard (when you don't step into troubles with system functions and Unicode) but porting libraries can be very hard, because some of them are rather complex and many include C coding -- and porting that stuff is much harder.