I understand the change matplotlib is making toward isinstance over duck-typing (the duck-typing doesn't work with e.g. open). But instead of spreading lots of basestring cruft throughout our codebase, could we continue to use is_string_like with the basestring cruft built into it. That would contain the py2/py3 checking to utils/misc.py. [eventually py2 checking will need to be deprecated too -- can we contain the impact?]