I'm getting an error while executing a function from a module in PyCharm 5:
/System/Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7 /Users/apple/Dropbox/PycharmProjects/work/2-chapter.py
...
...
AttributeError: 'module' object has no attribute 'corpus'
That is supposed to be nltk.corpus.
After having played with Project Structure (in Preferences) and adding there both /usr/local/lib/python2.7/site-packages and /Library/Python/2.7/site-packages paths, nothing still works out.

I am wondering whether I need to add this path as well /System/Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7 ?
The problem is I don't have it. I only have path ...Python.framework/Versions/3.5, although I have already installed python 2.7 as well and the interpreter uses python 2.7.5.
The PYTHONPATH is:
$ echo $PYTHONPATH
:/usr/local/lib/python2.7/site-packages
I also tried adding
import sys
sys.path.append("/usr/local/lib/python2.7/site-packages")
to the module I'm talking about, it also didn't work.
