Simple import in python 3 errors with complaint about bytes

Mike Boyle moboyle79 at
Tue Oct 21 01:29:39 CEST 2014

I'm modifying an extension written with the c-api to have a datatype of quaternions <>, with one of the goals being python 3 support.  It works nicely in python 2.7, but for python 3.x gives an error that I can't find anywhere on the google.  The directory looks like this:

    quaternion/ contains a line like this:

    from .numpy_quaternion import quaternion

But when it hits that line, python 3 throws its hands up in disgust:

> python -c 'import quaternion'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Users/mynamehere/.continuum/anaconda/envs/py3k/lib/python3.4/site-packages/quaternion/", line 3, in <module>
    from .numpy_quaternion import quaternion
TypeError: __import__() argument 1 must be str, not bytes

The only thing before that line is `import numpy as np`, which typically works just fine.  Obviously, I'm using python3.4 to compile and (attempt to) import (with a conda environment), so it's not something as dumb as using the wrong python.  Also, this is the result for both me on my laptop and Travis-CI <>, so it doesn't seem to be anything peculiar to my installation.  I've posted this question on stackoverflow, but haven't gotten much interest; the only responder suggested I ask here instead.

Any ideas what's going wrong, or where I can go from here?


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