Why refer to these as two separate languages? Right now, the vast majority of Python's most popular libraries and packages support both 2.7 and 3.4+ with a sin

Why refer to these as two separate languages? Right now, the vast majority of Python's most popular libraries and packages support both 2.7 and 3.4+ with a single code base. We are a Python shop, and we are doing the same with all our new projects as well. There's a little bit of extra awareness you have to have to do certain things (metaclasses, for instance), but the overhead is no more onerous than, say, following well-defined coding conventions.