Were you having a problem with this? exceptions is a mapping (to exc) defined in pptx/__init__.py for reasons I can't quite remember, something like the exceptions name was a Python global or something.

https://github.com/scanny/python-pptx/blob/master/pptx/__init__.py#L10

I was getting a module not found error on that line, I overlooked the mapping to exc though. This PR fixed the problem for me but maybe the issue was actually something with my local environment. Looks like its not a problem on my windows machine, only a problem on my mac, will look at it more tonight.

Yes, now that you mention it, I get that same error sometimes when things are not right somewhere else. I don't think I've narrowed down when that is, maybe when I haven't entered the virtual machine or something. If you can look out for specifically what fixes it (without the patch) maybe we can track it down and put in something useful by way of an error message or something.

Could be what happens if pptx is not found in sys.path; I seem to remember something vaguely like that. Maybe if you run certain development operations when you're not in the project directory and don't have python-pptx installed in "editable" (i.e. pip install -e ...) mode.

Going to close this PR. Found this nice surprise in my __init__.py
#import pptx.exc as exceptions
import sys
#sys.modules['pptx.exceptions'] = exceptions
Uncommenting those lines fixed the problem...now to figure out how those got commented out in the first place.