After a recent upgrade of numpy (1.13.1 -> 1.6.0), my code is failing where I provide unicode objects as filenames.
Previously they were allowed. Now that are not, and I *must* provide a (py2) str or bytearray only.

# str is OK
$ python2.7 -c "from numpy.compat import py3k; print py3k.os_fspath('123')"
123

# unicode is not
$ python -c "from numpy.compat import py3k; print py3k.os_fspath(u'123')"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/numpy/compat/py3k.py", line 237, in os_fspath
    "not " + path_type.__name__)
TypeError: expected str, bytes or os.PathLike object, not unicode

But this enforcement of "str, bytes or os.PathLike" comes from:
   https://docs.python.org/3/library/os.html
where in Python 3 str is a unicode, and moreover, os.fspath allows 

$ python3 -c "import os; print(os.fspath(u'123'))"   # unicode str
123
$ python3 -c "import os; print(os.fspath('123'))"   # also unicode str
123

.... so...  shouldn't py3k.os_fspath allow py2 unicode obejcts.

- Stu