OK, I give up. In parting I will point out that the official Python 2 documentation says "basestring() This abstract type is the superclass for str and unicode. It cannot be called or instantiated, but it can be used to test whether an object is an instance of str or unicode. isinstance(obj, basestring) is equivalent to isinstance(obj, (str, unicode))." That's exactly what the code we are converting (much of which was written years before Python 3 even existed) was doing. As for the idea that we weren't really "planning to use it as logical text" (ignoring the fact that _everyone_ used Python 2 str objects to represent logical text back in 2003, and ignoring the fact that the repro case given at the top of this report converts the 8-bit string value to Unicode -- why else would it do that except to use the value as "logical text"?) ... well, I don't know where to start. I'm done here. :->}