Ubuntu 16.04 Django 1.11.5 virtualenv opencv
Evert's comment was correct. I followed his steps and got a different, but similar, error. It turns out I had to install libxrender1.
Here are the steps I used:

activate my virtual environment
uninstall opencv-python
sudo apt-get install libsm6
reinstall opencv-python
sudo apt-get install libxrender1
I'm new to Ubuntu, and also fairly new to web development, so I am hoping there is some obvious thing I am missing. 
My problem is as follows: I have a box running Ubuntu 16.04 and I have my Django project with a virtualenv. With the virtualenv activated, I ran pip install opencv-python, and it seemed to work (all the files seem to be where I would think they need to be (env/lib/python3.5/site-packages/{cv2,numpy}).
But when I run manage.py, I get an error that traces back to __init__.py in the opencv package: 

ImportError: libSM.so.6: cannot open shared object file: No such file or directory.

I get the same error when I run python interactively in the virtualenv and try to import cv2.
Is .cv2 in the error a namespace? Is there an way I can get more information or do a python search for the namespace?