Sometimes finding the correct version of Python used in a virtual environment can be a problem. This blog post provides some good tips on how to fix the problem. http://takluyver.github.io/posts/i-cant-import-it.html
While installing TensorFlow on a Mac running El Capitan I kept getting one of those crazy Python errors that are impossible to decipher. Thanks to Stackoverflow which always saves me while coding I found out the problem. It is apparently “due to the System Integrity Protection introduced in OS X El Capitan.” The fix is copied below for the next time I run into this error. Thank you for the tip Kof.
sudo pip install --upgrade $TF_BINARY_URL --user python