Why refer to these as two separate languages?  Right now, the vast majority of Python&#x27;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&#x27;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.